[NFC] Enforce use of `Type::` on type names (#2434)

76 files changed, 2204 insertions, 2049 deletions

diff --git a/src/abi/js.h b/src/abi/js.h
index 89e3f0087..de74899b6 100644
--- a/src/abi/js.h
+++ b/src/abi/js.h
@@ -67,14 +67,14 @@ ensureScratchMemoryHelpers(Module* wasm,
     wasm->addFunction(std::move(func));
   };
 
-  ensureImport(SCRATCH_LOAD_I32, {i32}, i32);
-  ensureImport(SCRATCH_STORE_I32, {i32, i32}, none);
-  ensureImport(SCRATCH_LOAD_I64, {}, i64);
-  ensureImport(SCRATCH_STORE_I64, {i64}, none);
-  ensureImport(SCRATCH_LOAD_F32, {}, f32);
-  ensureImport(SCRATCH_STORE_F32, {f32}, none);
-  ensureImport(SCRATCH_LOAD_F64, {}, f64);
-  ensureImport(SCRATCH_STORE_F64, {f64}, none);
+  ensureImport(SCRATCH_LOAD_I32, {Type::i32}, Type::i32);
+  ensureImport(SCRATCH_STORE_I32, {Type::i32, Type::i32}, Type::none);
+  ensureImport(SCRATCH_LOAD_I64, {}, Type::i64);
+  ensureImport(SCRATCH_STORE_I64, {Type::i64}, Type::none);
+  ensureImport(SCRATCH_LOAD_F32, {}, Type::f32);
+  ensureImport(SCRATCH_STORE_F32, {Type::f32}, Type::none);
+  ensureImport(SCRATCH_LOAD_F64, {}, Type::f64);
+  ensureImport(SCRATCH_STORE_F64, {Type::f64}, Type::none);
 }
 
 inline bool isScratchMemoryHelper(cashew::IString name) {
diff --git a/src/abi/stack.h b/src/abi/stack.h
index 265a7af6e..c06caa2d0 100644
--- a/src/abi/stack.h
+++ b/src/abi/stack.h
@@ -88,7 +88,7 @@ getStackSpace(Index local, Function* func, Index size, Module& wasm) {
     local, builder.makeGlobalGet(stackPointer->name, PointerType)));
   // TODO: add stack max check
   Expression* added;
-  if (PointerType == i32) {
+  if (PointerType == Type::i32) {
     added = builder.makeBinary(AddInt32,
                                builder.makeLocalGet(local, PointerType),
                                builder.makeConst(Literal(int32_t(size))));
@@ -104,7 +104,7 @@ getStackSpace(Index local, Function* func, Index size, Module& wasm) {
   FindAllPointers<Return> finder(func->body);
   for (auto** ptr : finder.list) {
     auto* ret = (*ptr)->cast<Return>();
-    if (ret->value && ret->value->type != unreachable) {
+    if (ret->value && ret->value->type != Type::unreachable) {
       // handle the returned value
       auto* block = builder.makeBlock();
       auto temp = builder.addVar(func, ret->value->type);
@@ -120,10 +120,10 @@ getStackSpace(Index local, Function* func, Index size, Module& wasm) {
     }
   }
   // add stack restores to the body
-  if (func->body->type == none) {
+  if (func->body->type == Type::none) {
     block->list.push_back(func->body);
     block->list.push_back(makeStackRestore());
-  } else if (func->body->type == unreachable) {
+  } else if (func->body->type == Type::unreachable) {
     block->list.push_back(func->body);
     // no need to restore the old stack value, we're gone anyhow
   } else {
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index b30a1f6da..1f1805379 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -430,7 +430,7 @@ public:
     // zero
     bool import;
     IString module, base;
-    MappedGlobal() : type(none), import(false) {}
+    MappedGlobal() : type(Type::none), import(false) {}
     MappedGlobal(Type type) : type(type), import(false) {}
     MappedGlobal(Type type, bool import, IString module, IString base)
       : type(type), import(import), module(module), base(base) {}
@@ -456,7 +456,7 @@ public:
 private:
   void allocateGlobal(IString name, Type type, Literal value = Literal()) {
     assert(mappedGlobals.find(name) == mappedGlobals.end());
-    if (value.type == none) {
+    if (value.type == Type::none) {
       value = Literal::makeZero(type);
     }
     mappedGlobals.emplace(name, MappedGlobal(type));
@@ -529,12 +529,8 @@ private:
         // ok since in JS, double can contain everything i32 and f32 can).
         for (size_t i = 0; i < params.size(); i++) {
           if (mergedParams.size() > i) {
-            // TODO: Is this dead?
-            // if (mergedParams[i] == Type::none) {
-            //   mergedParams[i] = params[i]; // use a more concrete type
-            // } else
             if (mergedParams[i] != params[i]) {
-              mergedParams[i] = f64; // overloaded type, make it a double
+              mergedParams[i] = Type::f64; // overloaded type, make it a double
             }
           } else {
             mergedParams.push_back(params[i]); // add a new param
@@ -557,7 +553,7 @@ private:
   }
 
   Type getResultTypeOfCallUsingParent(Ref parent, AsmData* data) {
-    auto result = none;
+    Type result = Type::none;
     if (!!parent) {
       // if the parent is a seq, we cannot be the last element in it (we would
       // have a coercion, which would be the parent), so we must be (us,
@@ -642,18 +638,18 @@ private:
 
     if (op == PLUS) {
       return isInteger ? BinaryOp::AddInt32
-                       : (leftType == f32 ? BinaryOp::AddFloat32
-                                          : BinaryOp::AddFloat64);
+                       : (leftType == Type::f32 ? BinaryOp::AddFloat32
+                                                : BinaryOp::AddFloat64);
     }
     if (op == MINUS) {
       return isInteger ? BinaryOp::SubInt32
-                       : (leftType == f32 ? BinaryOp::SubFloat32
-                                          : BinaryOp::SubFloat64);
+                       : (leftType == Type::f32 ? BinaryOp::SubFloat32
+                                                : BinaryOp::SubFloat64);
     }
     if (op == MUL) {
       return isInteger ? BinaryOp::MulInt32
-                       : (leftType == f32 ? BinaryOp::MulFloat32
-                                          : BinaryOp::MulFloat64);
+                       : (leftType == Type::f32 ? BinaryOp::MulFloat32
+                                                : BinaryOp::MulFloat64);
     }
     if (op == AND) {
       return BinaryOp::AndInt32;
@@ -674,14 +670,14 @@ private:
       return BinaryOp::ShrUInt32;
     }
     if (op == EQ) {
-      return isInteger
-               ? BinaryOp::EqInt32
-               : (leftType == f32 ? BinaryOp::EqFloat32 : BinaryOp::EqFloat64);
+      return isInteger ? BinaryOp::EqInt32
+                       : (leftType == Type::f32 ? BinaryOp::EqFloat32
+                                                : BinaryOp::EqFloat64);
     }
     if (op == NE) {
-      return isInteger
-               ? BinaryOp::NeInt32
-               : (leftType == f32 ? BinaryOp::NeFloat32 : BinaryOp::NeFloat64);
+      return isInteger ? BinaryOp::NeInt32
+                       : (leftType == Type::f32 ? BinaryOp::NeFloat32
+                                                : BinaryOp::NeFloat64);
     }
 
     bool isUnsigned = isUnsignedCoercion(left) || isUnsignedCoercion(right);
@@ -690,7 +686,8 @@ private:
       if (isInteger) {
         return isUnsigned ? BinaryOp::DivUInt32 : BinaryOp::DivSInt32;
       }
-      return leftType == f32 ? BinaryOp::DivFloat32 : BinaryOp::DivFloat64;
+      return leftType == Type::f32 ? BinaryOp::DivFloat32
+                                   : BinaryOp::DivFloat64;
     }
     if (op == MOD) {
       if (isInteger) {
@@ -703,25 +700,25 @@ private:
       if (isInteger) {
         return isUnsigned ? BinaryOp::GeUInt32 : BinaryOp::GeSInt32;
       }
-      return leftType == f32 ? BinaryOp::GeFloat32 : BinaryOp::GeFloat64;
+      return leftType == Type::f32 ? BinaryOp::GeFloat32 : BinaryOp::GeFloat64;
     }
     if (op == GT) {
       if (isInteger) {
         return isUnsigned ? BinaryOp::GtUInt32 : BinaryOp::GtSInt32;
       }
-      return leftType == f32 ? BinaryOp::GtFloat32 : BinaryOp::GtFloat64;
+      return leftType == Type::f32 ? BinaryOp::GtFloat32 : BinaryOp::GtFloat64;
     }
     if (op == LE) {
       if (isInteger) {
         return isUnsigned ? BinaryOp::LeUInt32 : BinaryOp::LeSInt32;
       }
-      return leftType == f32 ? BinaryOp::LeFloat32 : BinaryOp::LeFloat64;
+      return leftType == Type::f32 ? BinaryOp::LeFloat32 : BinaryOp::LeFloat64;
     }
     if (op == LT) {
       if (isInteger) {
         return isUnsigned ? BinaryOp::LtUInt32 : BinaryOp::LtSInt32;
       }
-      return leftType == f32 ? BinaryOp::LtFloat32 : BinaryOp::LtFloat64;
+      return leftType == Type::f32 ? BinaryOp::LtFloat32 : BinaryOp::LtFloat64;
     }
     abort_on("bad wasm binary op", op);
     abort(); // avoid warning
@@ -785,7 +782,7 @@ private:
 
   Literal getLiteral(Ref ast) {
     Literal ret = checkLiteral(ast);
-    assert(ret.type != none);
+    assert(ret.type != Type::none);
     return ret;
   }
 
@@ -805,15 +802,15 @@ private:
       if (base == ABS) {
         assert(operands && operands->size() == 1);
         Type type = (*operands)[0]->type;
-        if (type == i32) {
+        if (type == Type::i32) {
           sig = Signature(Type::i32, Type::i32);
           return true;
         }
-        if (type == f32) {
+        if (type == Type::f32) {
           sig = Signature(Type::f32, Type::f32);
           return true;
         }
-        if (type == f64) {
+        if (type == Type::f64) {
           sig = Signature(Type::f64, Type::f64);
           return true;
         }
@@ -838,7 +835,7 @@ private:
   }
 
   Expression* truncateToInt32(Expression* value) {
-    if (value->type == i64) {
+    if (value->type == Type::i64) {
       return builder.makeUnary(UnaryOp::WrapInt64, value);
     }
     // either i32, or a call_import whose type we don't know yet (but would be
@@ -895,7 +892,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
     import->name = MEMORY_BASE;
     import->module = "env";
     import->base = MEMORY_BASE;
-    import->type = i32;
+    import->type = Type::i32;
     wasm.addGlobal(import);
   }
 
@@ -905,7 +902,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
     import->name = TABLE_BASE;
     import->module = "env";
     import->base = TABLE_BASE;
-    import->type = i32;
+    import->type = Type::i32;
     wasm.addGlobal(import);
   }
 
@@ -1277,7 +1274,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
           //       when function pointer casts are emulated.
           if (wasm.table.segments.size() == 0) {
             wasm.table.segments.emplace_back(
-              builder.makeGlobalGet(Name(TABLE_BASE), i32));
+              builder.makeGlobalGet(Name(TABLE_BASE), Type::i32));
           }
           auto& segment = wasm.table.segments[0];
           functionTableStarts[name] =
@@ -1332,7 +1329,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
           auto value = pair[1]->getInteger();
           auto* global =
             builder.makeGlobal(key,
-                               i32,
+                               Type::i32,
                                builder.makeConst(Literal(int32_t(value))),
                                Builder::Immutable);
           wasm.addGlobal(global);
@@ -1512,11 +1509,11 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
                    curr->operands[i]->type == Type::unreachable);
             // overloaded, upgrade to f64
             switch (curr->operands[i]->type) {
-              case i32:
+              case Type::i32:
                 curr->operands[i] = parent->builder.makeUnary(
                   ConvertSInt32ToFloat64, curr->operands[i]);
                 break;
-              case f32:
+              case Type::f32:
                 curr->operands[i] =
                   parent->builder.makeUnary(PromoteFloat32, curr->operands[i]);
                 break;
@@ -1533,18 +1530,18 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
             // we use a JS f64 value which is the most general, and convert to
             // it
             switch (old) {
-              case i32: {
+              case Type::i32: {
                 Unary* trunc =
                   parent->builder.makeUnary(TruncSFloat64ToInt32, curr);
                 replaceCurrent(
                   makeTrappingUnary(trunc, parent->trappingFunctions));
                 break;
               }
-              case f32: {
+              case Type::f32: {
                 replaceCurrent(parent->builder.makeUnary(DemoteFloat64, curr));
                 break;
               }
-              case none: {
+              case Type::none: {
                 // this function returns a value, but we are not using it, so it
                 // must be dropped. autodrop will do that for us.
                 break;
@@ -1553,7 +1550,7 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
                 WASM_UNREACHABLE("unexpected type");
             }
           } else {
-            assert(old == none);
+            assert(old == Type::none);
             // we don't want a return value here, but the import does provide
             // one autodrop will do that for us.
           }
@@ -1651,8 +1648,8 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
               i > 0 && (expressionStack[i - 1]->is<Block>() ||
                         expressionStack[i - 1]->is<Loop>() ||
                         expressionStack[i - 1]->is<If>());
-            if (i == 0 || parentIsStructure || exp->type == none ||
-                exp->type == unreachable) {
+            if (i == 0 || parentIsStructure || exp->type == Type::none ||
+                exp->type == Type::unreachable) {
               if (debugLocations.count(exp) > 0) {
                 // already present, so look back up
                 i++;
@@ -1746,33 +1743,34 @@ void Asm2WasmBuilder::processAsm(Ref ast) {
     //    returns x / y
     auto* func = wasm.getFunction(udivmoddi4);
     Builder::clearLocals(func);
-    Index xl = Builder::addParam(func, "xl", i32),
-          xh = Builder::addParam(func, "xh", i32),
-          yl = Builder::addParam(func, "yl", i32),
-          yh = Builder::addParam(func, "yh", i32),
-          r = Builder::addParam(func, "r", i32),
-          x64 = Builder::addVar(func, "x64", i64),
-          y64 = Builder::addVar(func, "y64", i64);
+    Index xl = Builder::addParam(func, "xl", Type::i32),
+          xh = Builder::addParam(func, "xh", Type::i32),
+          yl = Builder::addParam(func, "yl", Type::i32),
+          yh = Builder::addParam(func, "yh", Type::i32),
+          r = Builder::addParam(func, "r", Type::i32),
+          x64 = Builder::addVar(func, "x64", Type::i64),
+          y64 = Builder::addVar(func, "y64", Type::i64);
     auto* body = allocator.alloc<Block>();
     body->list.push_back(
       builder.makeLocalSet(x64, I64Utilities::recreateI64(builder, xl, xh)));
     body->list.push_back(
       builder.makeLocalSet(y64, I64Utilities::recreateI64(builder, yl, yh)));
-    body->list.push_back(builder.makeIf(
-      builder.makeLocalGet(r, i32),
-      builder.makeStore(8,
-                        0,
-                        8,
-                        builder.makeLocalGet(r, i32),
-                        builder.makeBinary(RemUInt64,
-                                           builder.makeLocalGet(x64, i64),
-                                           builder.makeLocalGet(y64, i64)),
-                        i64)));
     body->list.push_back(
-      builder.makeLocalSet(x64,
-                           builder.makeBinary(DivUInt64,
-                                              builder.makeLocalGet(x64, i64),
-                                              builder.makeLocalGet(y64, i64))));
+      builder.makeIf(builder.makeLocalGet(r, Type::i32),
+                     builder.makeStore(
+                       8,
+                       0,
+                       8,
+                       builder.makeLocalGet(r, Type::i32),
+                       builder.makeBinary(RemUInt64,
+                                          builder.makeLocalGet(x64, Type::i64),
+                                          builder.makeLocalGet(y64, Type::i64)),
+                       Type::i64)));
+    body->list.push_back(builder.makeLocalSet(
+      x64,
+      builder.makeBinary(DivUInt64,
+                         builder.makeLocalGet(x64, Type::i64),
+                         builder.makeLocalGet(y64, Type::i64))));
     body->list.push_back(
       builder.makeGlobalSet(tempRet0, I64Utilities::getI64High(builder, x64)));
     body->list.push_back(I64Utilities::getI64Low(builder, x64));
@@ -1841,7 +1839,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       return;
     }
     addedI32Temp = true;
-    Builder::addVar(function, I32_TEMP, i32);
+    Builder::addVar(function, I32_TEMP, Type::i32);
     functionVariables.insert(I32_TEMP);
     asmData.addVar(I32_TEMP, ASM_INT);
   };
@@ -1867,7 +1865,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       if (name == DEBUGGER) {
         Call* call = allocator.alloc<Call>();
         call->target = DEBUGGER;
-        call->type = none;
+        call->type = Type::none;
         static bool addedImport = false;
         if (!addedImport) {
           addedImport = true;
@@ -1945,13 +1943,14 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       if (ret->valueType != ret->value->type) {
         // in asm.js we have some implicit coercions that we must do explicitly
         // here
-        if (ret->valueType == f32 && ret->value->type == f64) {
+        if (ret->valueType == Type::f32 && ret->value->type == Type::f64) {
           auto conv = allocator.alloc<Unary>();
           conv->op = DemoteFloat64;
           conv->value = ret->value;
           conv->type = Type::f32;
           ret->value = conv;
-        } else if (ret->valueType == f64 && ret->value->type == f32) {
+        } else if (ret->valueType == Type::f64 &&
+                   ret->value->type == Type::f32) {
           ret->value = ensureDouble(ret->value);
         } else {
           abort_on("bad sub[] types", ast);
@@ -1963,9 +1962,9 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
     if (what == BINARY) {
       if ((ast[1] == OR || ast[1] == TRSHIFT) && ast[3]->isNumber() &&
           ast[3]->getNumber() == 0) {
-        auto ret =
-          process(ast[2]); // just look through the ()|0 or ()>>>0 coercion
-        fixCallType(ret, i32);
+        // just look through the ()|0 or ()>>>0 coercion
+        auto ret = process(ast[2]);
+        fixCallType(ret, Type::i32);
         return ret;
       }
       auto ret = allocator.alloc<Binary>();
@@ -1981,7 +1980,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
         call->target = F64_REM;
         call->operands.push_back(ensureDouble(ret->left));
         call->operands.push_back(ensureDouble(ret->right));
-        call->type = f64;
+        call->type = Type::f64;
         static bool addedImport = false;
         if (!addedImport) {
           addedImport = true;
@@ -2013,22 +2012,22 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
     } else if (what == UNARY_PREFIX) {
       if (ast[1] == PLUS) {
         Literal literal = checkLiteral(ast);
-        if (literal.type != none) {
+        if (literal.type != Type::none) {
           return builder.makeConst(literal);
         }
         auto ret = process(ast[2]); // we are a +() coercion
-        if (ret->type == i32) {
+        if (ret->type == Type::i32) {
           auto conv = allocator.alloc<Unary>();
           conv->op = isUnsignedCoercion(ast[2]) ? ConvertUInt32ToFloat64
                                                 : ConvertSInt32ToFloat64;
           conv->value = ret;
-          conv->type = Type::f64;
+          conv->type = Type::Type::f64;
           return conv;
         }
-        if (ret->type == f32) {
+        if (ret->type == Type::f32) {
           return ensureDouble(ret);
         }
-        fixCallType(ret, f64);
+        fixCallType(ret, Type::f64);
         return ret;
       } else if (ast[1] == MINUS) {
         if (ast[2]->isNumber() ||
@@ -2067,7 +2066,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           // if we have an unsigned coercion on us, it is an unsigned op
           Expression* expr = process(ast[2][2]);
           bool isSigned = !isParentUnsignedCoercion(astStackHelper.getParent());
-          bool isF64 = expr->type == f64;
+          bool isF64 = expr->type == Type::f64;
           UnaryOp op;
           if (isSigned && isF64) {
             op = UnaryOp::TruncSFloat64ToInt32;
@@ -2092,7 +2091,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
         auto ret = allocator.alloc<Unary>();
         ret->op = EqZInt32;
         ret->value = process(ast[2]);
-        ret->type = i32;
+        ret->type = Type::i32;
         return ret;
       }
       abort_on("bad unary", ast);
@@ -2125,34 +2124,34 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
         if (name == Math_fround) {
           assert(ast[2]->size() == 1);
           Literal lit = checkLiteral(ast[2][0], false /* raw is float */);
-          if (lit.type == f64) {
+          if (lit.type == Type::f64) {
             return builder.makeConst(Literal((float)lit.getf64()));
           }
           auto ret = allocator.alloc<Unary>();
           ret->value = process(ast[2][0]);
-          if (ret->value->type == f64) {
+          if (ret->value->type == Type::f64) {
             ret->op = DemoteFloat64;
-          } else if (ret->value->type == i32) {
+          } else if (ret->value->type == Type::i32) {
             if (isUnsignedCoercion(ast[2][0])) {
               ret->op = ConvertUInt32ToFloat32;
             } else {
               ret->op = ConvertSInt32ToFloat32;
             }
-          } else if (ret->value->type == f32) {
+          } else if (ret->value->type == Type::f32) {
             return ret->value;
-          } else if (ret->value->type == none) { // call, etc.
-            ret->value->type = f32;
+          } else if (ret->value->type == Type::none) { // call, etc.
+            ret->value->type = Type::f32;
             return ret->value;
           } else {
             abort_on("confusing fround target", ast[2][0]);
           }
-          ret->type = f32;
+          ret->type = Type::f32;
           return ret;
         }
         if (name == Math_abs) {
           // overloaded on type: i32, f32 or f64
           Expression* value = process(ast[2][0]);
-          if (value->type == i32) {
+          if (value->type == Type::i32) {
             // No wasm support, so use a temp local
             ensureI32Temp();
             auto set = allocator.alloc<LocalSet>();
@@ -2163,7 +2162,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
             auto get = [&]() {
               auto ret = allocator.alloc<LocalGet>();
               ret->index = function->getLocalIndex(I32_TEMP);
-              ret->type = i32;
+              ret->type = Type::i32;
               return ret;
             };
             auto isNegative = allocator.alloc<Binary>();
@@ -2177,18 +2176,18 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
             flip->op = SubInt32;
             flip->left = builder.makeConst(Literal(0));
             flip->right = get();
-            flip->type = i32;
+            flip->type = Type::i32;
             auto select = allocator.alloc<Select>();
             select->ifTrue = flip;
             select->ifFalse = get();
             select->condition = isNegative;
-            select->type = i32;
+            select->type = Type::i32;
             block->list.push_back(select);
             block->finalize();
             return block;
-          } else if (value->type == f32 || value->type == f64) {
+          } else if (value->type == Type::f32 || value->type == Type::f64) {
             auto ret = allocator.alloc<Unary>();
-            ret->op = value->type == f32 ? AbsFloat32 : AbsFloat64;
+            ret->op = value->type == Type::f32 ? AbsFloat32 : AbsFloat64;
             ret->value = value;
             ret->type = value->type;
             return ret;
@@ -2201,12 +2200,12 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           Expression* value = process(ast[2][0]);
           auto ret = allocator.alloc<Unary>();
           ret->value = value;
-          if (value->type == f32) {
+          if (value->type == Type::f32) {
             ret->op = name == Math_floor
                         ? FloorFloat32
                         : name == Math_ceil ? CeilFloat32 : SqrtFloat32;
             ret->type = value->type;
-          } else if (value->type == f64) {
+          } else if (value->type == Type::f64) {
             ret->op = name == Math_floor
                         ? FloorFloat64
                         : name == Math_ceil ? CeilFloat64 : SqrtFloat64;
@@ -2223,9 +2222,9 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           auto ret = allocator.alloc<Binary>();
           ret->left = process(ast[2][0]);
           ret->right = process(ast[2][1]);
-          if (ret->left->type == f32) {
+          if (ret->left->type == Type::f32) {
             ret->op = name == Math_max ? MaxFloat32 : MinFloat32;
-          } else if (ret->left->type == f64) {
+          } else if (ret->left->type == Type::f64) {
             ret->op = name == Math_max ? MaxFloat64 : MinFloat64;
           } else {
             Fatal() << "min/max only work on float/double in asm.js and wasm";
@@ -2335,27 +2334,28 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
             case 'l': {
               auto align = num == 2 ? ast[2][1]->getInteger() : 0;
               if (name == LOAD1) {
-                return builder.makeLoad(1, true, 0, 1, process(ast[2][0]), i32);
+                return builder.makeLoad(
+                  1, true, 0, 1, process(ast[2][0]), Type::i32);
               }
               if (name == LOAD2) {
                 return builder.makeLoad(
-                  2, true, 0, indexOr(align, 2), process(ast[2][0]), i32);
+                  2, true, 0, indexOr(align, 2), process(ast[2][0]), Type::i32);
               }
               if (name == LOAD4) {
                 return builder.makeLoad(
-                  4, true, 0, indexOr(align, 4), process(ast[2][0]), i32);
+                  4, true, 0, indexOr(align, 4), process(ast[2][0]), Type::i32);
               }
               if (name == LOAD8) {
                 return builder.makeLoad(
-                  8, true, 0, indexOr(align, 8), process(ast[2][0]), i64);
+                  8, true, 0, indexOr(align, 8), process(ast[2][0]), Type::i64);
               }
               if (name == LOADF) {
                 return builder.makeLoad(
-                  4, true, 0, indexOr(align, 4), process(ast[2][0]), f32);
+                  4, true, 0, indexOr(align, 4), process(ast[2][0]), Type::f32);
               }
               if (name == LOADD) {
                 return builder.makeLoad(
-                  8, true, 0, indexOr(align, 8), process(ast[2][0]), f64);
+                  8, true, 0, indexOr(align, 8), process(ast[2][0]), Type::f64);
               }
               break;
             }
@@ -2363,7 +2363,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
               auto align = num == 3 ? ast[2][2]->getInteger() : 0;
               if (name == STORE1) {
                 return builder.makeStore(
-                  1, 0, 1, process(ast[2][0]), process(ast[2][1]), i32);
+                  1, 0, 1, process(ast[2][0]), process(ast[2][1]), Type::i32);
               }
               if (name == STORE2) {
                 return builder.makeStore(2,
@@ -2371,7 +2371,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                                          indexOr(align, 2),
                                          process(ast[2][0]),
                                          process(ast[2][1]),
-                                         i32);
+                                         Type::i32);
               }
               if (name == STORE4) {
                 return builder.makeStore(4,
@@ -2379,7 +2379,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                                          indexOr(align, 4),
                                          process(ast[2][0]),
                                          process(ast[2][1]),
-                                         i32);
+                                         Type::i32);
               }
               if (name == STORE8) {
                 return builder.makeStore(8,
@@ -2387,17 +2387,21 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                                          indexOr(align, 8),
                                          process(ast[2][0]),
                                          process(ast[2][1]),
-                                         i64);
+                                         Type::i64);
               }
               if (name == STOREF) {
                 auto* value = process(ast[2][1]);
-                if (value->type == f64) {
+                if (value->type == Type::f64) {
                   // asm.js allows storing a double to HEAPF32, we must cast
                   // here
                   value = builder.makeUnary(DemoteFloat64, value);
                 }
-                return builder.makeStore(
-                  4, 0, indexOr(align, 4), process(ast[2][0]), value, f32);
+                return builder.makeStore(4,
+                                         0,
+                                         indexOr(align, 4),
+                                         process(ast[2][0]),
+                                         value,
+                                         Type::f32);
               }
               if (name == STORED) {
                 return builder.makeStore(8,
@@ -2405,7 +2409,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                                          indexOr(align, 8),
                                          process(ast[2][0]),
                                          process(ast[2][1]),
-                                         f64);
+                                         Type::f64);
               }
               break;
             }
@@ -2415,11 +2419,11 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                 if (name == I64) {
                   // no-op "coercion" / "cast", although we also tolerate i64(0)
                   // for constants that fit in i32
-                  if (value->type == i32) {
+                  if (value->type == Type::i32) {
                     return builder.makeConst(
                       Literal(int64_t(value->cast<Const>()->value.geti32())));
                   } else {
-                    fixCallType(value, i64);
+                    fixCallType(value, Type::i64);
                     return value;
                   }
                 }
@@ -2497,7 +2501,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                   return builder.makeUnary(UnaryOp::PopcntInt64, value);
                 }
                 if (name == I64_ATOMICS_LOAD) {
-                  return builder.makeAtomicLoad(8, 0, value, i64);
+                  return builder.makeAtomicLoad(8, 0, value, Type::i64);
                 }
               } else if (num == 2) { // 2 params,binary
                 if (name == I64_CONST) {
@@ -2587,37 +2591,37 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                 // atomics
                 if (name == I64_ATOMICS_STORE) {
                   wasm.memory.shared = true;
-                  return builder.makeAtomicStore(8, 0, left, right, i64);
+                  return builder.makeAtomicStore(8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_ADD) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::Add, 8, 0, left, right, i64);
+                    AtomicRMWOp::Add, 8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_SUB) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::Sub, 8, 0, left, right, i64);
+                    AtomicRMWOp::Sub, 8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_AND) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::And, 8, 0, left, right, i64);
+                    AtomicRMWOp::And, 8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_OR) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::Or, 8, 0, left, right, i64);
+                    AtomicRMWOp::Or, 8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_XOR) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::Xor, 8, 0, left, right, i64);
+                    AtomicRMWOp::Xor, 8, 0, left, right, Type::i64);
                 }
                 if (name == I64_ATOMICS_EXCHANGE) {
                   wasm.memory.shared = true;
                   return builder.makeAtomicRMW(
-                    AtomicRMWOp::Xchg, 8, 0, left, right, i64);
+                    AtomicRMWOp::Xchg, 8, 0, left, right, Type::i64);
                 }
               } else if (num == 3) {
                 if (name == I64_ATOMICS_COMPAREEXCHANGE) {
@@ -2627,7 +2631,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                                                    process(ast[2][0]),
                                                    process(ast[2][1]),
                                                    process(ast[2][2]),
-                                                   i64);
+                                                   Type::i64);
                 }
               }
               break;
@@ -2723,13 +2727,13 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       // we don't know the table offset yet. emit target = target +
       // callImport(tableName), which we fix up later when we know how asm
       // function tables are layed out inside the wasm table.
-      ret->target =
-        builder.makeBinary(BinaryOp::AddInt32,
-                           ret->target,
-                           builder.makeCall(target[1]->getIString(), {}, i32));
+      ret->target = builder.makeBinary(
+        BinaryOp::AddInt32,
+        ret->target,
+        builder.makeCall(target[1]->getIString(), {}, Type::i32));
       return ret;
     } else if (what == RETURN) {
-      Type type = !!ast[1] ? detectWasmType(ast[1], &asmData) : none;
+      Type type = !!ast[1] ? detectWasmType(ast[1], &asmData) : Type::none;
       if (seenReturn) {
         assert(function->sig.results == type);
       } else {
@@ -3004,7 +3008,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                   auto conv = allocator.alloc<Unary>();
                   conv->op = ReinterpretFloat32;
                   conv->value = process(writtenValue);
-                  if (conv->value->type == f64) {
+                  if (conv->value->type == Type::f64) {
                     // this has an implicit f64->f32 in the write to memory
                     conv->value = builder.makeUnary(DemoteFloat64, conv->value);
                   }
@@ -3070,26 +3074,26 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
         // outside if not
         Break* breakWhenNotMatching = nullptr;
 
-        if (br->condition->type == i32) {
+        if (br->condition->type == Type::i32) {
           Binary* offsetor = allocator.alloc<Binary>();
           offsetor->op = BinaryOp::SubInt32;
           offsetor->left = br->condition;
           offsetor->right = builder.makeConst(Literal(int32_t(min)));
-          offsetor->type = i32;
+          offsetor->type = Type::i32;
           br->condition = offsetor;
         } else {
-          assert(br->condition->type == i64);
+          assert(br->condition->type == Type::i64);
           // 64-bit condition. after offsetting it must be in a reasonable
           // range, but the offsetting itself must be 64-bit
           Binary* offsetor = allocator.alloc<Binary>();
           offsetor->op = BinaryOp::SubInt64;
           offsetor->left = br->condition;
           offsetor->right = builder.makeConst(Literal(int64_t(min)));
-          offsetor->type = i64;
+          offsetor->type = Type::i64;
           // the switch itself can be 32-bit, as the range is in a reasonable
           // range. so after offsetting, we need to make sure there are no high
           // bits, then we can just look at the lower 32 bits
-          auto temp = Builder::addVar(function, i64);
+          auto temp = Builder::addVar(function, Type::i64);
           auto* block = builder.makeBlock();
           block->list.push_back(builder.makeLocalSet(temp, offsetor));
           // if high bits, we can break to the default (we'll fill in the name
@@ -3100,10 +3104,10 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
             builder.makeUnary(
               UnaryOp::WrapInt64,
               builder.makeBinary(BinaryOp::ShrUInt64,
-                                 builder.makeLocalGet(temp, i64),
+                                 builder.makeLocalGet(temp, Type::i64),
                                  builder.makeConst(Literal(int64_t(32))))));
           block->list.push_back(breakWhenNotMatching);
-          block->list.push_back(builder.makeLocalGet(temp, i64));
+          block->list.push_back(builder.makeLocalGet(temp, Type::i64));
           block->finalize();
           br->condition = builder.makeUnary(UnaryOp::WrapInt64, block);
         }
@@ -3173,7 +3177,8 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
           } else {
             name = nameMapper.pushLabelName("switch-case");
             auto* iff = builder.makeIf(
-              builder.makeBinary(br->condition->type == i32 ? EqInt32 : EqInt64,
+              builder.makeBinary(br->condition->type == Type::i32 ? EqInt32
+                                                                  : EqInt64,
                                  builder.makeLocalGet(var, br->condition->type),
                                  builder.makeConst(getLiteral(condition))),
               builder.makeBreak(name),
diff --git a/src/asmjs/asm_v_wasm.cpp b/src/asmjs/asm_v_wasm.cpp
index 5959db43e..b499bd6e2 100644
--- a/src/asmjs/asm_v_wasm.cpp
+++ b/src/asmjs/asm_v_wasm.cpp
@@ -43,24 +43,24 @@ Type asmToWasmType(AsmType asmType) {
 
 AsmType wasmToAsmType(Type type) {
   switch (type) {
-    case i32:
+    case Type::i32:
       return ASM_INT;
-    case f32:
+    case Type::f32:
       return ASM_FLOAT;
-    case f64:
+    case Type::f64:
       return ASM_DOUBLE;
-    case i64:
+    case Type::i64:
       return ASM_INT64;
-    case v128:
+    case Type::v128:
       assert(false && "v128 not implemented yet");
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
       assert(false && "reference types are not supported by asm2wasm");
-    case none:
+    case Type::none:
       return ASM_NONE;
-    case unreachable:
+    case Type::unreachable:
       WASM_UNREACHABLE("invalid type");
   }
   WASM_UNREACHABLE("invalid type");
@@ -68,27 +68,27 @@ AsmType wasmToAsmType(Type type) {
 
 char getSig(Type type) {
   switch (type) {
-    case i32:
+    case Type::i32:
       return 'i';
-    case i64:
+    case Type::i64:
       return 'j';
-    case f32:
+    case Type::f32:
       return 'f';
-    case f64:
+    case Type::f64:
       return 'd';
-    case v128:
+    case Type::v128:
       return 'V';
-    case funcref:
+    case Type::funcref:
       return 'F';
-    case anyref:
+    case Type::anyref:
       return 'A';
-    case nullref:
+    case Type::nullref:
       return 'N';
-    case exnref:
+    case Type::exnref:
       return 'E';
-    case none:
+    case Type::none:
       return 'v';
-    case unreachable:
+    case Type::unreachable:
       WASM_UNREACHABLE("invalid type");
   }
   WASM_UNREACHABLE("invalid type");
@@ -109,14 +109,14 @@ std::string getSig(Type results, Type params) {
 }
 
 Expression* ensureDouble(Expression* expr, MixedArena& allocator) {
-  if (expr->type == f32) {
+  if (expr->type == Type::f32) {
     auto conv = allocator.alloc<Unary>();
     conv->op = PromoteFloat32;
     conv->value = expr;
     conv->type = Type::f64;
     return conv;
   }
-  assert(expr->type == f64);
+  assert(expr->type == Type::f64);
   return expr;
 }
 
diff --git a/src/binaryen-c.cpp b/src/binaryen-c.cpp
index a98ff3407..44830cd75 100644
--- a/src/binaryen-c.cpp
+++ b/src/binaryen-c.cpp
@@ -272,17 +272,17 @@ extern "C" {
 
 // Core types
 
-BinaryenType BinaryenTypeNone(void) { return none; }
-BinaryenType BinaryenTypeInt32(void) { return i32; }
-BinaryenType BinaryenTypeInt64(void) { return i64; }
-BinaryenType BinaryenTypeFloat32(void) { return f32; }
-BinaryenType BinaryenTypeFloat64(void) { return f64; }
-BinaryenType BinaryenTypeVec128(void) { return v128; }
-BinaryenType BinaryenTypeFuncref(void) { return funcref; }
-BinaryenType BinaryenTypeAnyref(void) { return anyref; }
-BinaryenType BinaryenTypeNullref(void) { return nullref; }
-BinaryenType BinaryenTypeExnref(void) { return exnref; }
-BinaryenType BinaryenTypeUnreachable(void) { return unreachable; }
+BinaryenType BinaryenTypeNone(void) { return Type::none; }
+BinaryenType BinaryenTypeInt32(void) { return Type::i32; }
+BinaryenType BinaryenTypeInt64(void) { return Type::i64; }
+BinaryenType BinaryenTypeFloat32(void) { return Type::f32; }
+BinaryenType BinaryenTypeFloat64(void) { return Type::f64; }
+BinaryenType BinaryenTypeVec128(void) { return Type::v128; }
+BinaryenType BinaryenTypeFuncref(void) { return Type::funcref; }
+BinaryenType BinaryenTypeAnyref(void) { return Type::anyref; }
+BinaryenType BinaryenTypeNullref(void) { return Type::nullref; }
+BinaryenType BinaryenTypeExnref(void) { return Type::exnref; }
+BinaryenType BinaryenTypeUnreachable(void) { return Type::unreachable; }
 BinaryenType BinaryenTypeAuto(void) { return uint32_t(-1); }
 
 BinaryenType BinaryenTypeCreate(BinaryenType* types, uint32_t numTypes) {
@@ -321,11 +321,11 @@ void BinaryenTypeExpand(BinaryenType t, BinaryenType* buf) {
   }
 }
 
-WASM_DEPRECATED BinaryenType BinaryenNone(void) { return none; }
-WASM_DEPRECATED BinaryenType BinaryenInt32(void) { return i32; }
-WASM_DEPRECATED BinaryenType BinaryenInt64(void) { return i64; }
-WASM_DEPRECATED BinaryenType BinaryenFloat32(void) { return f32; }
-WASM_DEPRECATED BinaryenType BinaryenFloat64(void) { return f64; }
+WASM_DEPRECATED BinaryenType BinaryenNone(void) { return Type::none; }
+WASM_DEPRECATED BinaryenType BinaryenInt32(void) { return Type::i32; }
+WASM_DEPRECATED BinaryenType BinaryenInt64(void) { return Type::i64; }
+WASM_DEPRECATED BinaryenType BinaryenFloat32(void) { return Type::f32; }
+WASM_DEPRECATED BinaryenType BinaryenFloat64(void) { return Type::f64; }
 WASM_DEPRECATED BinaryenType BinaryenUndefined(void) { return uint32_t(-1); }
 
 // Expression ids
diff --git a/src/cfg/Relooper.cpp b/src/cfg/Relooper.cpp
index d46b39a8e..0c9b581bd 100644
--- a/src/cfg/Relooper.cpp
+++ b/src/cfg/Relooper.cpp
@@ -378,10 +378,10 @@ wasm::Expression* Block::Render(RelooperBuilder& Builder, bool InLoop) {
         // breaking on Outer leads to the content in NextOuter
         Outer->name = CurrName;
         NextOuter->list.push_back(CurrContent);
-        // if this is not a dead end, also need to break to the outside
-        // this is both an optimization, and avoids incorrectness as adding
-        // a brak in unreachable code can make a place look reachable that isn't
-        if (CurrContent->type != wasm::unreachable) {
+        // if this is not a dead end, also need to break to the outside this is
+        // both an optimization, and avoids incorrectness as adding a break in
+        // unreachable code can make a place look reachable that isn't
+        if (CurrContent->type != wasm::Type::unreachable) {
           NextOuter->list.push_back(Builder.makeBreak(SwitchLeave));
         }
         // prepare for more nesting
@@ -835,7 +835,7 @@ private:
         }
       }
       NewList.push_back(Curr);
-      if (Curr->type == wasm::unreachable) {
+      if (Curr->type == wasm::Type::unreachable) {
         SeenUnreachableType = true;
       }
     };
diff --git a/src/cfg/Relooper.h b/src/cfg/Relooper.h
index 6b38816d0..f13d02711 100644
--- a/src/cfg/Relooper.h
+++ b/src/cfg/Relooper.h
@@ -50,7 +50,7 @@ public:
     : wasm::Builder(wasm), labelHelper(labelHelper) {}
 
   wasm::LocalGet* makeGetLabel() {
-    return makeLocalGet(labelHelper, wasm::i32);
+    return makeLocalGet(labelHelper, wasm::Type::i32);
   }
   wasm::LocalSet* makeSetLabel(wasm::Index value) {
     return makeLocalSet(labelHelper, makeConst(wasm::Literal(int32_t(value))));
diff --git a/src/dataflow/node.h b/src/dataflow/node.h
index 612a2f613..bb537afc2 100644
--- a/src/dataflow/node.h
+++ b/src/dataflow/node.h
@@ -163,7 +163,7 @@ struct Node {
       case Zext:
         return getValue(0)->getWasmType();
       case Bad:
-        return unreachable;
+        return wasm::Type::unreachable;
       default:
         WASM_UNREACHABLE("invalid node type");
     }
diff --git a/src/gen-s-parser.inc b/src/gen-s-parser.inc
index eb5626b3f..eab7be468 100644
--- a/src/gen-s-parser.inc
+++ b/src/gen-s-parser.inc
@@ -10,7 +10,7 @@ switch (op[0]) {
   case 'a': {
     switch (op[1]) {
       case 'n':
-        if (strcmp(op, "anyref.pop") == 0) { return makePop(anyref); }
+        if (strcmp(op, "anyref.pop") == 0) { return makePop(Type::anyref); }
         goto parse_error;
       case 't': {
         switch (op[7]) {
@@ -84,7 +84,7 @@ switch (op[0]) {
         if (strcmp(op, "else") == 0) { return makeThenOrElse(s); }
         goto parse_error;
       case 'x':
-        if (strcmp(op, "exnref.pop") == 0) { return makePop(exnref); }
+        if (strcmp(op, "exnref.pop") == 0) { return makePop(Type::exnref); }
         goto parse_error;
       default: goto parse_error;
     }
@@ -116,7 +116,7 @@ switch (op[0]) {
                       case 'n': {
                         switch (op[7]) {
                           case 's':
-                            if (strcmp(op, "f32.const") == 0) { return makeConst(s, f32); }
+                            if (strcmp(op, "f32.const") == 0) { return makeConst(s, Type::f32); }
                             goto parse_error;
                           case 'v': {
                             switch (op[13]) {
@@ -191,7 +191,7 @@ switch (op[0]) {
                     if (strcmp(op, "f32.le") == 0) { return makeBinary(s, BinaryOp::LeFloat32); }
                     goto parse_error;
                   case 'o':
-                    if (strcmp(op, "f32.load") == 0) { return makeLoad(s, f32, /*isAtomic=*/false); }
+                    if (strcmp(op, "f32.load") == 0) { return makeLoad(s, Type::f32, /*isAtomic=*/false); }
                     goto parse_error;
                   case 't':
                     if (strcmp(op, "f32.lt") == 0) { return makeBinary(s, BinaryOp::LtFloat32); }
@@ -228,7 +228,7 @@ switch (op[0]) {
                 }
               }
               case 'p':
-                if (strcmp(op, "f32.pop") == 0) { return makePop(f32); }
+                if (strcmp(op, "f32.pop") == 0) { return makePop(Type::f32); }
                 goto parse_error;
               case 'r':
                 if (strcmp(op, "f32.reinterpret_i32") == 0) { return makeUnary(s, UnaryOp::ReinterpretInt32); }
@@ -239,7 +239,7 @@ switch (op[0]) {
                     if (strcmp(op, "f32.sqrt") == 0) { return makeUnary(s, UnaryOp::SqrtFloat32); }
                     goto parse_error;
                   case 't':
-                    if (strcmp(op, "f32.store") == 0) { return makeStore(s, f32, /*isAtomic=*/false); }
+                    if (strcmp(op, "f32.store") == 0) { return makeStore(s, Type::f32, /*isAtomic=*/false); }
                     goto parse_error;
                   case 'u':
                     if (strcmp(op, "f32.sub") == 0) { return makeBinary(s, BinaryOp::SubFloat32); }
@@ -397,7 +397,7 @@ switch (op[0]) {
                       case 'n': {
                         switch (op[7]) {
                           case 's':
-                            if (strcmp(op, "f64.const") == 0) { return makeConst(s, f64); }
+                            if (strcmp(op, "f64.const") == 0) { return makeConst(s, Type::f64); }
                             goto parse_error;
                           case 'v': {
                             switch (op[13]) {
@@ -464,7 +464,7 @@ switch (op[0]) {
                     if (strcmp(op, "f64.le") == 0) { return makeBinary(s, BinaryOp::LeFloat64); }
                     goto parse_error;
                   case 'o':
-                    if (strcmp(op, "f64.load") == 0) { return makeLoad(s, f64, /*isAtomic=*/false); }
+                    if (strcmp(op, "f64.load") == 0) { return makeLoad(s, Type::f64, /*isAtomic=*/false); }
                     goto parse_error;
                   case 't':
                     if (strcmp(op, "f64.lt") == 0) { return makeBinary(s, BinaryOp::LtFloat64); }
@@ -503,7 +503,7 @@ switch (op[0]) {
               case 'p': {
                 switch (op[5]) {
                   case 'o':
-                    if (strcmp(op, "f64.pop") == 0) { return makePop(f64); }
+                    if (strcmp(op, "f64.pop") == 0) { return makePop(Type::f64); }
                     goto parse_error;
                   case 'r':
                     if (strcmp(op, "f64.promote_f32") == 0) { return makeUnary(s, UnaryOp::PromoteFloat32); }
@@ -520,7 +520,7 @@ switch (op[0]) {
                     if (strcmp(op, "f64.sqrt") == 0) { return makeUnary(s, UnaryOp::SqrtFloat64); }
                     goto parse_error;
                   case 't':
-                    if (strcmp(op, "f64.store") == 0) { return makeStore(s, f64, /*isAtomic=*/false); }
+                    if (strcmp(op, "f64.store") == 0) { return makeStore(s, Type::f64, /*isAtomic=*/false); }
                     goto parse_error;
                   case 'u':
                     if (strcmp(op, "f64.sub") == 0) { return makeBinary(s, BinaryOp::SubFloat64); }
@@ -654,7 +654,7 @@ switch (op[0]) {
         }
       }
       case 'u':
-        if (strcmp(op, "funcref.pop") == 0) { return makePop(funcref); }
+        if (strcmp(op, "funcref.pop") == 0) { return makePop(Type::funcref); }
         goto parse_error;
       default: goto parse_error;
     }
@@ -944,13 +944,13 @@ switch (op[0]) {
                       case 'l': {
                         switch (op[15]) {
                           case '\0':
-                            if (strcmp(op, "i32.atomic.load") == 0) { return makeLoad(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.load") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           case '1':
-                            if (strcmp(op, "i32.atomic.load16_u") == 0) { return makeLoad(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.load16_u") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           case '8':
-                            if (strcmp(op, "i32.atomic.load8_u") == 0) { return makeLoad(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.load8_u") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -962,30 +962,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[16]) {
                                   case 'd':
-                                    if (strcmp(op, "i32.atomic.rmw.add") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw.add") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i32.atomic.rmw.and") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw.and") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i32.atomic.rmw.cmpxchg") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw.cmpxchg") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i32.atomic.rmw.or") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw.or") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i32.atomic.rmw.sub") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw.sub") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[16]) {
                                   case 'c':
-                                    if (strcmp(op, "i32.atomic.rmw.xchg") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw.xchg") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i32.atomic.rmw.xor") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw.xor") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -998,30 +998,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[18]) {
                                   case 'd':
-                                    if (strcmp(op, "i32.atomic.rmw16.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw16.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i32.atomic.rmw16.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw16.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i32.atomic.rmw16.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw16.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i32.atomic.rmw16.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw16.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i32.atomic.rmw16.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw16.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[18]) {
                                   case 'c':
-                                    if (strcmp(op, "i32.atomic.rmw16.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw16.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i32.atomic.rmw16.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw16.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1034,30 +1034,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[17]) {
                                   case 'd':
-                                    if (strcmp(op, "i32.atomic.rmw8.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw8.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i32.atomic.rmw8.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw8.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i32.atomic.rmw8.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw8.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i32.atomic.rmw8.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw8.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i32.atomic.rmw8.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                if (strcmp(op, "i32.atomic.rmw8.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[17]) {
                                   case 'c':
-                                    if (strcmp(op, "i32.atomic.rmw8.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw8.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i32.atomic.rmw8.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i32); }
+                                    if (strcmp(op, "i32.atomic.rmw8.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i32); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1071,19 +1071,19 @@ switch (op[0]) {
                       case 's': {
                         switch (op[16]) {
                           case '\0':
-                            if (strcmp(op, "i32.atomic.store") == 0) { return makeStore(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.store") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           case '1':
-                            if (strcmp(op, "i32.atomic.store16") == 0) { return makeStore(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.store16") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           case '8':
-                            if (strcmp(op, "i32.atomic.store8") == 0) { return makeStore(s, i32, /*isAtomic=*/true); }
+                            if (strcmp(op, "i32.atomic.store8") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/true); }
                             goto parse_error;
                           default: goto parse_error;
                         }
                       }
                       case 'w':
-                        if (strcmp(op, "i32.atomic.wait") == 0) { return makeAtomicWait(s, i32); }
+                        if (strcmp(op, "i32.atomic.wait") == 0) { return makeAtomicWait(s, Type::i32); }
                         goto parse_error;
                       default: goto parse_error;
                     }
@@ -1097,7 +1097,7 @@ switch (op[0]) {
                     if (strcmp(op, "i32.clz") == 0) { return makeUnary(s, UnaryOp::ClzInt32); }
                     goto parse_error;
                   case 'o':
-                    if (strcmp(op, "i32.const") == 0) { return makeConst(s, i32); }
+                    if (strcmp(op, "i32.const") == 0) { return makeConst(s, Type::i32); }
                     goto parse_error;
                   case 't':
                     if (strcmp(op, "i32.ctz") == 0) { return makeUnary(s, UnaryOp::CtzInt32); }
@@ -1186,15 +1186,15 @@ switch (op[0]) {
                   case 'o': {
                     switch (op[8]) {
                       case '\0':
-                        if (strcmp(op, "i32.load") == 0) { return makeLoad(s, i32, /*isAtomic=*/false); }
+                        if (strcmp(op, "i32.load") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/false); }
                         goto parse_error;
                       case '1': {
                         switch (op[11]) {
                           case 's':
-                            if (strcmp(op, "i32.load16_s") == 0) { return makeLoad(s, i32, /*isAtomic=*/false); }
+                            if (strcmp(op, "i32.load16_s") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/false); }
                             goto parse_error;
                           case 'u':
-                            if (strcmp(op, "i32.load16_u") == 0) { return makeLoad(s, i32, /*isAtomic=*/false); }
+                            if (strcmp(op, "i32.load16_u") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/false); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1202,10 +1202,10 @@ switch (op[0]) {
                       case '8': {
                         switch (op[10]) {
                           case 's':
-                            if (strcmp(op, "i32.load8_s") == 0) { return makeLoad(s, i32, /*isAtomic=*/false); }
+                            if (strcmp(op, "i32.load8_s") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/false); }
                             goto parse_error;
                           case 'u':
-                            if (strcmp(op, "i32.load8_u") == 0) { return makeLoad(s, i32, /*isAtomic=*/false); }
+                            if (strcmp(op, "i32.load8_u") == 0) { return makeLoad(s, Type::i32, /*isAtomic=*/false); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1239,7 +1239,7 @@ switch (op[0]) {
               case 'p': {
                 switch (op[7]) {
                   case '\0':
-                    if (strcmp(op, "i32.pop") == 0) { return makePop(i32); }
+                    if (strcmp(op, "i32.pop") == 0) { return makePop(Type::i32); }
                     goto parse_error;
                   case 'c':
                     if (strcmp(op, "i32.popcnt") == 0) { return makeUnary(s, UnaryOp::PopcntInt32); }
@@ -1306,13 +1306,13 @@ switch (op[0]) {
                   case 't': {
                     switch (op[9]) {
                       case '\0':
-                        if (strcmp(op, "i32.store") == 0) { return makeStore(s, i32, /*isAtomic=*/false); }
+                        if (strcmp(op, "i32.store") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/false); }
                         goto parse_error;
                       case '1':
-                        if (strcmp(op, "i32.store16") == 0) { return makeStore(s, i32, /*isAtomic=*/false); }
+                        if (strcmp(op, "i32.store16") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/false); }
                         goto parse_error;
                       case '8':
-                        if (strcmp(op, "i32.store8") == 0) { return makeStore(s, i32, /*isAtomic=*/false); }
+                        if (strcmp(op, "i32.store8") == 0) { return makeStore(s, Type::i32, /*isAtomic=*/false); }
                         goto parse_error;
                       default: goto parse_error;
                     }
@@ -1621,16 +1621,16 @@ switch (op[0]) {
                       case 'l': {
                         switch (op[15]) {
                           case '\0':
-                            if (strcmp(op, "i64.atomic.load") == 0) { return makeLoad(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.load") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '1':
-                            if (strcmp(op, "i64.atomic.load16_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.load16_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '3':
-                            if (strcmp(op, "i64.atomic.load32_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.load32_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '8':
-                            if (strcmp(op, "i64.atomic.load8_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.load8_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1642,30 +1642,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[16]) {
                                   case 'd':
-                                    if (strcmp(op, "i64.atomic.rmw.add") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw.add") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i64.atomic.rmw.and") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw.and") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i64.atomic.rmw.cmpxchg") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw.cmpxchg") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i64.atomic.rmw.or") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw.or") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i64.atomic.rmw.sub") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw.sub") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[16]) {
                                   case 'c':
-                                    if (strcmp(op, "i64.atomic.rmw.xchg") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw.xchg") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i64.atomic.rmw.xor") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw.xor") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1678,30 +1678,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[18]) {
                                   case 'd':
-                                    if (strcmp(op, "i64.atomic.rmw16.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw16.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i64.atomic.rmw16.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw16.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i64.atomic.rmw16.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw16.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i64.atomic.rmw16.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw16.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i64.atomic.rmw16.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw16.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[18]) {
                                   case 'c':
-                                    if (strcmp(op, "i64.atomic.rmw16.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw16.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i64.atomic.rmw16.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw16.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1714,30 +1714,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[18]) {
                                   case 'd':
-                                    if (strcmp(op, "i64.atomic.rmw32.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw32.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i64.atomic.rmw32.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw32.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i64.atomic.rmw32.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw32.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i64.atomic.rmw32.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw32.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i64.atomic.rmw32.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw32.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[18]) {
                                   case 'c':
-                                    if (strcmp(op, "i64.atomic.rmw32.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw32.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i64.atomic.rmw32.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw32.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1750,30 +1750,30 @@ switch (op[0]) {
                               case 'a': {
                                 switch (op[17]) {
                                   case 'd':
-                                    if (strcmp(op, "i64.atomic.rmw8.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw8.add_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'n':
-                                    if (strcmp(op, "i64.atomic.rmw8.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw8.and_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
                               }
                               case 'c':
-                                if (strcmp(op, "i64.atomic.rmw8.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw8.cmpxchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'o':
-                                if (strcmp(op, "i64.atomic.rmw8.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw8.or_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 's':
-                                if (strcmp(op, "i64.atomic.rmw8.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                if (strcmp(op, "i64.atomic.rmw8.sub_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                 goto parse_error;
                               case 'x': {
                                 switch (op[17]) {
                                   case 'c':
-                                    if (strcmp(op, "i64.atomic.rmw8.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw8.xchg_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   case 'o':
-                                    if (strcmp(op, "i64.atomic.rmw8.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, i64); }
+                                    if (strcmp(op, "i64.atomic.rmw8.xor_u") == 0) { return makeAtomicRMWOrCmpxchg(s, Type::i64); }
                                     goto parse_error;
                                   default: goto parse_error;
                                 }
@@ -1787,22 +1787,22 @@ switch (op[0]) {
                       case 's': {
                         switch (op[16]) {
                           case '\0':
-                            if (strcmp(op, "i64.atomic.store") == 0) { return makeStore(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.store") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '1':
-                            if (strcmp(op, "i64.atomic.store16") == 0) { return makeStore(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.store16") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '3':
-                            if (strcmp(op, "i64.atomic.store32") == 0) { return makeStore(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.store32") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           case '8':
-                            if (strcmp(op, "i64.atomic.store8") == 0) { return makeStore(s, i64, /*isAtomic=*/true); }
+                            if (strcmp(op, "i64.atomic.store8") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/true); }
                             goto parse_error;
                           default: goto parse_error;
                         }
                       }
                       case 'w':
-                        if (strcmp(op, "i64.atomic.wait") == 0) { return makeAtomicWait(s, i64); }
+                        if (strcmp(op, "i64.atomic.wait") == 0) { return makeAtomicWait(s, Type::i64); }
                         goto parse_error;
                       default: goto parse_error;
                     }
@@ -1816,7 +1816,7 @@ switch (op[0]) {
                     if (strcmp(op, "i64.clz") == 0) { return makeUnary(s, UnaryOp::ClzInt64); }
                     goto parse_error;
                   case 'o':
-                    if (strcmp(op, "i64.const") == 0) { return makeConst(s, i64); }
+                    if (strcmp(op, "i64.const") == 0) { return makeConst(s, Type::i64); }
                     goto parse_error;
                   case 't':
                     if (strcmp(op, "i64.ctz") == 0) { return makeUnary(s, UnaryOp::CtzInt64); }
@@ -1919,15 +1919,15 @@ switch (op[0]) {
                   case 'o': {
                     switch (op[8]) {
                       case '\0':
-                        if (strcmp(op, "i64.load") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                        if (strcmp(op, "i64.load") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                         goto parse_error;
                       case '1': {
                         switch (op[11]) {
                           case 's':
-                            if (strcmp(op, "i64.load16_s") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load16_s") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           case 'u':
-                            if (strcmp(op, "i64.load16_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load16_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1935,10 +1935,10 @@ switch (op[0]) {
                       case '3': {
                         switch (op[11]) {
                           case 's':
-                            if (strcmp(op, "i64.load32_s") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load32_s") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           case 'u':
-                            if (strcmp(op, "i64.load32_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load32_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1946,10 +1946,10 @@ switch (op[0]) {
                       case '8': {
                         switch (op[10]) {
                           case 's':
-                            if (strcmp(op, "i64.load8_s") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load8_s") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           case 'u':
-                            if (strcmp(op, "i64.load8_u") == 0) { return makeLoad(s, i64, /*isAtomic=*/false); }
+                            if (strcmp(op, "i64.load8_u") == 0) { return makeLoad(s, Type::i64, /*isAtomic=*/false); }
                             goto parse_error;
                           default: goto parse_error;
                         }
@@ -1983,7 +1983,7 @@ switch (op[0]) {
               case 'p': {
                 switch (op[7]) {
                   case '\0':
-                    if (strcmp(op, "i64.pop") == 0) { return makePop(i64); }
+                    if (strcmp(op, "i64.pop") == 0) { return makePop(Type::i64); }
                     goto parse_error;
                   case 'c':
                     if (strcmp(op, "i64.popcnt") == 0) { return makeUnary(s, UnaryOp::PopcntInt64); }
@@ -2050,16 +2050,16 @@ switch (op[0]) {
                   case 't': {
                     switch (op[9]) {
                       case '\0':
-                        if (strcmp(op, "i64.store") == 0) { return makeStore(s, i64, /*isAtomic=*/false); }
+                        if (strcmp(op, "i64.store") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/false); }
                         goto parse_error;
                       case '1':
-                        if (strcmp(op, "i64.store16") == 0) { return makeStore(s, i64, /*isAtomic=*/false); }
+                        if (strcmp(op, "i64.store16") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/false); }
                         goto parse_error;
                       case '3':
-                        if (strcmp(op, "i64.store32") == 0) { return makeStore(s, i64, /*isAtomic=*/false); }
+                        if (strcmp(op, "i64.store32") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/false); }
                         goto parse_error;
                       case '8':
-                        if (strcmp(op, "i64.store8") == 0) { return makeStore(s, i64, /*isAtomic=*/false); }
+                        if (strcmp(op, "i64.store8") == 0) { return makeStore(s, Type::i64, /*isAtomic=*/false); }
                         goto parse_error;
                       default: goto parse_error;
                     }
@@ -2489,7 +2489,7 @@ switch (op[0]) {
         if (strcmp(op, "nop") == 0) { return makeNop(); }
         goto parse_error;
       case 'u':
-        if (strcmp(op, "nullref.pop") == 0) { return makePop(nullref); }
+        if (strcmp(op, "nullref.pop") == 0) { return makePop(Type::nullref); }
         goto parse_error;
       default: goto parse_error;
     }
@@ -2589,10 +2589,10 @@ switch (op[0]) {
                 if (strcmp(op, "v128.bitselect") == 0) { return makeSIMDTernary(s, SIMDTernaryOp::Bitselect); }
                 goto parse_error;
               case 'c':
-                if (strcmp(op, "v128.const") == 0) { return makeConst(s, v128); }
+                if (strcmp(op, "v128.const") == 0) { return makeConst(s, Type::v128); }
                 goto parse_error;
               case 'l':
-                if (strcmp(op, "v128.load") == 0) { return makeLoad(s, v128, /*isAtomic=*/false); }
+                if (strcmp(op, "v128.load") == 0) { return makeLoad(s, Type::v128, /*isAtomic=*/false); }
                 goto parse_error;
               case 'n':
                 if (strcmp(op, "v128.not") == 0) { return makeUnary(s, UnaryOp::NotVec128); }
@@ -2601,10 +2601,10 @@ switch (op[0]) {
                 if (strcmp(op, "v128.or") == 0) { return makeBinary(s, BinaryOp::OrVec128); }
                 goto parse_error;
               case 'p':
-                if (strcmp(op, "v128.pop") == 0) { return makePop(v128); }
+                if (strcmp(op, "v128.pop") == 0) { return makePop(Type::v128); }
                 goto parse_error;
               case 's':
-                if (strcmp(op, "v128.store") == 0) { return makeStore(s, v128, /*isAtomic=*/false); }
+                if (strcmp(op, "v128.store") == 0) { return makeStore(s, Type::v128, /*isAtomic=*/false); }
                 goto parse_error;
               case 'x':
                 if (strcmp(op, "v128.xor") == 0) { return makeBinary(s, BinaryOp::XorVec128); }
diff --git a/src/ir/ExpressionAnalyzer.cpp b/src/ir/ExpressionAnalyzer.cpp
index 4b9869ddd..a61af9ce5 100644
--- a/src/ir/ExpressionAnalyzer.cpp
+++ b/src/ir/ExpressionAnalyzer.cpp
@@ -151,7 +151,8 @@ template<typename T> void visitImmediates(Expression* curr, T& visitor) {
     }
     void visitLoad(Load* curr) {
       visitor.visitInt(curr->bytes);
-      if (curr->type != unreachable && curr->bytes < curr->type.getByteSize()) {
+      if (curr->type != Type::unreachable &&
+          curr->bytes < curr->type.getByteSize()) {
         visitor.visitInt(curr->signed_);
       }
       visitor.visitAddress(curr->offset);
diff --git a/src/ir/ReFinalize.cpp b/src/ir/ReFinalize.cpp
index 9243869a1..5e72850e6 100644
--- a/src/ir/ReFinalize.cpp
+++ b/src/ir/ReFinalize.cpp
@@ -21,7 +21,7 @@
 namespace wasm {
 
 static Type getValueType(Expression* value) {
-  return value ? value->type : none;
+  return value ? value->type : Type::none;
 }
 
 namespace {
@@ -41,7 +41,7 @@ void handleBranchForVisitBlock(T* curr, Name name, Module* module) {
 
 void ReFinalize::visitBlock(Block* curr) {
   if (curr->list.size() == 0) {
-    curr->type = none;
+    curr->type = Type::none;
     return;
   }
   // Get the least upper bound type of the last element and all branch return
@@ -54,14 +54,14 @@ void ReFinalize::visitBlock(Block* curr) {
       return;
     }
   }
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     return;
   }
   // type is none, but we might be unreachable
-  if (curr->type == none) {
+  if (curr->type == Type::none) {
     for (auto* child : curr->list) {
-      if (child->type == unreachable) {
-        curr->type = unreachable;
+      if (child->type == Type::unreachable) {
+        curr->type = Type::unreachable;
         break;
       }
     }
@@ -72,7 +72,7 @@ void ReFinalize::visitLoop(Loop* curr) { curr->finalize(); }
 void ReFinalize::visitBreak(Break* curr) {
   curr->finalize();
   auto valueType = getValueType(curr->value);
-  if (valueType == unreachable) {
+  if (valueType == Type::unreachable) {
     replaceUntaken(curr->value, curr->condition);
   } else {
     updateBreakValueType(curr->name, valueType);
@@ -81,7 +81,7 @@ void ReFinalize::visitBreak(Break* curr) {
 void ReFinalize::visitSwitch(Switch* curr) {
   curr->finalize();
   auto valueType = getValueType(curr->value);
-  if (valueType == unreachable) {
+  if (valueType == Type::unreachable) {
     replaceUntaken(curr->value, curr->condition);
   } else {
     for (auto target : curr->targets) {
@@ -164,7 +164,7 @@ void ReFinalize::updateBreakValueType(Name name, Type type) {
 // Replace an untaken branch/switch with an unreachable value.
 // A condition may also exist and may or may not be unreachable.
 void ReFinalize::replaceUntaken(Expression* value, Expression* condition) {
-  assert(value->type == unreachable);
+  assert(value->type == Type::unreachable);
   auto* replacement = value;
   if (condition) {
     Builder builder(*getModule());
diff --git a/src/ir/abstract.h b/src/ir/abstract.h
index 76215d07f..06a1cd41c 100644
--- a/src/ir/abstract.h
+++ b/src/ir/abstract.h
@@ -53,13 +53,13 @@ enum Op {
 // addition, AddInt32. If the op does not exist, it returns Invalid.
 inline UnaryOp getUnary(Type type, Op op) {
   switch (type) {
-    case i32: {
+    case Type::i32: {
       return InvalidUnary;
     }
-    case i64: {
+    case Type::i64: {
       return InvalidUnary;
     }
-    case f32: {
+    case Type::f32: {
       switch (op) {
         case Neg:
           return NegFloat32;
@@ -68,7 +68,7 @@ inline UnaryOp getUnary(Type type, Op op) {
       }
       break;
     }
-    case f64: {
+    case Type::f64: {
       switch (op) {
         case Neg:
           return NegFloat64;
@@ -77,15 +77,15 @@ inline UnaryOp getUnary(Type type, Op op) {
       }
       break;
     }
-    case v128: {
+    case Type::v128: {
       WASM_UNREACHABLE("v128 not implemented yet");
     }
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
-    case none:
-    case unreachable: {
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
+    case Type::none:
+    case Type::unreachable: {
       return InvalidUnary;
     }
   }
@@ -94,7 +94,7 @@ inline UnaryOp getUnary(Type type, Op op) {
 
 inline BinaryOp getBinary(Type type, Op op) {
   switch (type) {
-    case i32: {
+    case Type::i32: {
       switch (op) {
         case Add:
           return AddInt32;
@@ -131,7 +131,7 @@ inline BinaryOp getBinary(Type type, Op op) {
       }
       break;
     }
-    case i64: {
+    case Type::i64: {
       switch (op) {
         case Add:
           return AddInt64;
@@ -168,7 +168,7 @@ inline BinaryOp getBinary(Type type, Op op) {
       }
       break;
     }
-    case f32: {
+    case Type::f32: {
       switch (op) {
         case Add:
           return AddFloat32;
@@ -189,7 +189,7 @@ inline BinaryOp getBinary(Type type, Op op) {
       }
       break;
     }
-    case f64: {
+    case Type::f64: {
       switch (op) {
         case Add:
           return AddFloat64;
@@ -210,15 +210,15 @@ inline BinaryOp getBinary(Type type, Op op) {
       }
       break;
     }
-    case v128: {
+    case Type::v128: {
       WASM_UNREACHABLE("v128 not implemented yet");
     }
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
-    case none:
-    case unreachable: {
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
+    case Type::none:
+    case Type::unreachable: {
       return InvalidBinary;
     }
   }
diff --git a/src/ir/bits.h b/src/ir/bits.h
index cbac70d77..6b0697280 100644
--- a/src/ir/bits.h
+++ b/src/ir/bits.h
@@ -55,9 +55,9 @@ struct Bits {
   // gets the number of effective shifts a shift operation does. In
   // wasm, only 5 bits matter for 32-bit shifts, and 6 for 64.
   static Index getEffectiveShifts(Index amount, Type type) {
-    if (type == i32) {
+    if (type == Type::i32) {
       return amount & 31;
-    } else if (type == i64) {
+    } else if (type == Type::i64) {
       return amount & 63;
     }
     WASM_UNREACHABLE("unexpected type");
@@ -65,37 +65,41 @@ struct Bits {
 
   static Index getEffectiveShifts(Expression* expr) {
     auto* amount = expr->cast<Const>();
-    if (amount->type == i32) {
-      return getEffectiveShifts(amount->value.geti32(), i32);
-    } else if (amount->type == i64) {
-      return getEffectiveShifts(amount->value.geti64(), i64);
+    if (amount->type == Type::i32) {
+      return getEffectiveShifts(amount->value.geti32(), Type::i32);
+    } else if (amount->type == Type::i64) {
+      return getEffectiveShifts(amount->value.geti64(), Type::i64);
     }
     WASM_UNREACHABLE("unexpected type");
   }
 
   static Expression* makeSignExt(Expression* value, Index bytes, Module& wasm) {
-    if (value->type == i32) {
+    if (value->type == Type::i32) {
       if (bytes == 1 || bytes == 2) {
         auto shifts = bytes == 1 ? 24 : 16;
         Builder builder(wasm);
         return builder.makeBinary(
           ShrSInt32,
           builder.makeBinary(
-            ShlInt32, value, LiteralUtils::makeFromInt32(shifts, i32, wasm)),
-          LiteralUtils::makeFromInt32(shifts, i32, wasm));
+            ShlInt32,
+            value,
+            LiteralUtils::makeFromInt32(shifts, Type::i32, wasm)),
+          LiteralUtils::makeFromInt32(shifts, Type::i32, wasm));
       }
       assert(bytes == 4);
       return value; // nothing to do
     } else {
-      assert(value->type == i64);
+      assert(value->type == Type::i64);
       if (bytes == 1 || bytes == 2 || bytes == 4) {
         auto shifts = bytes == 1 ? 56 : (bytes == 2 ? 48 : 32);
         Builder builder(wasm);
         return builder.makeBinary(
           ShrSInt64,
           builder.makeBinary(
-            ShlInt64, value, LiteralUtils::makeFromInt32(shifts, i64, wasm)),
-          LiteralUtils::makeFromInt32(shifts, i64, wasm));
+            ShlInt64,
+            value,
+            LiteralUtils::makeFromInt32(shifts, Type::i64, wasm)),
+          LiteralUtils::makeFromInt32(shifts, Type::i64, wasm));
       }
       assert(bytes == 8);
       return value; // nothing to do
diff --git a/src/ir/block-utils.h b/src/ir/block-utils.h
index 153dd45b3..d3a4e0a64 100644
--- a/src/ir/block-utils.h
+++ b/src/ir/block-utils.h
@@ -51,7 +51,7 @@ simplifyToContents(Block* block, T* parent, bool allowTypeChange = false) {
       // inside is unreachable (if both concrete, must match, and since no name
       // on block, we can't be branched to, so if singleton is unreachable, so
       // is the block)
-      assert(block->type.isConcrete() && singleton->type == unreachable);
+      assert(block->type.isConcrete() && singleton->type == Type::unreachable);
       // we could replace with unreachable, but would need to update all
       // the parent's types
     }
diff --git a/src/ir/branch-utils.h b/src/ir/branch-utils.h
index a22301e54..363a9c9e2 100644
--- a/src/ir/branch-utils.h
+++ b/src/ir/branch-utils.h
@@ -28,17 +28,17 @@ namespace BranchUtils {
 // (unreachable)))
 
 inline bool isBranchReachable(Break* br) {
-  return !(br->value && br->value->type == unreachable) &&
-         !(br->condition && br->condition->type == unreachable);
+  return !(br->value && br->value->type == Type::unreachable) &&
+         !(br->condition && br->condition->type == Type::unreachable);
 }
 
 inline bool isBranchReachable(Switch* sw) {
-  return !(sw->value && sw->value->type == unreachable) &&
-         sw->condition->type != unreachable;
+  return !(sw->value && sw->value->type == Type::unreachable) &&
+         sw->condition->type != Type::unreachable;
 }
 
 inline bool isBranchReachable(BrOnExn* br) {
-  return br->exnref->type != unreachable;
+  return br->exnref->type != Type::unreachable;
 }
 
 inline bool isBranchReachable(Expression* expr) {
@@ -159,14 +159,16 @@ struct BranchSeeker : public PostWalker<BranchSeeker> {
 
   BranchSeeker(Name target) : target(target) {}
 
-  void noteFound(Expression* value) { noteFound(value ? value->type : none); }
+  void noteFound(Expression* value) {
+    noteFound(value ? value->type : Type::none);
+  }
 
   void noteFound(Type type) {
     found++;
     if (found == 1) {
-      valueType = unreachable;
+      valueType = Type::unreachable;
     }
-    if (type != unreachable) {
+    if (type != Type::unreachable) {
       valueType = type;
     }
   }
diff --git a/src/ir/effects.h b/src/ir/effects.h
index 6eb2da91d..9c8887333 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -209,7 +209,7 @@ struct EffectAnalyzer
     //      loop top, but no way to get out, then it is an infinite loop, and we
     //      consider that a branching side effect (note how the same logic does
     //      not apply to blocks).
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       branches = true;
     }
   }
diff --git a/src/ir/literal-utils.h b/src/ir/literal-utils.h
index 4bc79eee9..45119f2bd 100644
--- a/src/ir/literal-utils.h
+++ b/src/ir/literal-utils.h
@@ -34,7 +34,7 @@ inline Expression* makeFromInt32(int32_t x, Type type, Module& wasm) {
 inline Expression* makeZero(Type type, Module& wasm) {
   // TODO: Switch to using v128.const once V8 supports it
   // (https://bugs.chromium.org/p/v8/issues/detail?id=8460)
-  if (type == v128) {
+  if (type == Type::v128) {
     Builder builder(wasm);
     return builder.makeUnary(SplatVecI32x4,
                              builder.makeConst(Literal(int32_t(0))));
diff --git a/src/ir/load-utils.h b/src/ir/load-utils.h
index a3bf79c60..62c31ef4e 100644
--- a/src/ir/load-utils.h
+++ b/src/ir/load-utils.h
@@ -28,7 +28,7 @@ namespace LoadUtils {
 // fill in bits either signed or unsigned wise)
 inline bool isSignRelevant(Load* load) {
   auto type = load->type;
-  if (load->type == unreachable) {
+  if (load->type == Type::unreachable) {
     return false;
   }
   return !type.isFloat() && load->bytes < type.getByteSize();
diff --git a/src/ir/memory-utils.h b/src/ir/memory-utils.h
index c6b2fad18..13b356ba8 100644
--- a/src/ir/memory-utils.h
+++ b/src/ir/memory-utils.h
@@ -174,7 +174,7 @@ inline bool ensureLimitedSegments(Module& module) {
     // create the segment and add in all the data
     auto* c = module.allocator.alloc<Const>();
     c->value = Literal(int32_t(start));
-    c->type = i32;
+    c->type = Type::i32;
 
     Memory::Segment combined(c);
     for (Index j = i; j < memory.segments.size(); j++) {
diff --git a/src/ir/properties.h b/src/ir/properties.h
index f4c9686b6..01e78563d 100644
--- a/src/ir/properties.h
+++ b/src/ir/properties.h
@@ -156,7 +156,7 @@ inline Index getZeroExtBits(Expression* curr) {
 inline Expression* getFallthrough(Expression* curr) {
   // If the current node is unreachable, there is no value
   // falling through.
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     return curr;
   }
   if (auto* set = curr->dynCast<LocalSet>()) {
@@ -173,9 +173,9 @@ inline Expression* getFallthrough(Expression* curr) {
   } else if (auto* iff = curr->dynCast<If>()) {
     if (iff->ifFalse) {
       // Perhaps just one of the two actually returns.
-      if (iff->ifTrue->type == unreachable) {
+      if (iff->ifTrue->type == Type::unreachable) {
         return getFallthrough(iff->ifFalse);
-      } else if (iff->ifFalse->type == unreachable) {
+      } else if (iff->ifFalse->type == Type::unreachable) {
         return getFallthrough(iff->ifTrue);
       }
     }
diff --git a/src/ir/type-updating.h b/src/ir/type-updating.h
index d64ae0158..c028d3b5b 100644
--- a/src/ir/type-updating.h
+++ b/src/ir/type-updating.h
@@ -172,7 +172,7 @@ struct TypeUpdater
 
   // note the addition of a node
   void noteBreakChange(Name name, int change, Expression* value) {
-    noteBreakChange(name, change, value ? value->type : none);
+    noteBreakChange(name, change, value ? value->type : Type::none);
   }
 
   void noteBreakChange(Name name, int change, Type type) {
@@ -191,7 +191,7 @@ struct TypeUpdater
         makeBlockUnreachableIfNoFallThrough(block);
       } else if (change == 1 && info.numBreaks == 1) {
         // bumped to 1! the block may now be reachable
-        if (block->type != unreachable) {
+        if (block->type != Type::unreachable) {
           return; // was already reachable, had a fallthrough
         }
         changeTypeTo(block, type);
@@ -217,7 +217,7 @@ struct TypeUpdater
   // the one thing we need to do here is propagate unreachability,
   // no other change is possible
   void propagateTypesUp(Expression* curr) {
-    if (curr->type != unreachable) {
+    if (curr->type != Type::unreachable) {
       return;
     }
     while (1) {
@@ -227,7 +227,7 @@ struct TypeUpdater
         return;
       }
       // get ready to apply unreachability to this node
-      if (curr->type == unreachable) {
+      if (curr->type == Type::unreachable) {
         return; // already unreachable, stop here
       }
       // most nodes become unreachable if a child is unreachable,
@@ -239,23 +239,23 @@ struct TypeUpdater
         }
         // if the block has breaks, it can keep its type
         if (!block->name.is() || blockInfos[block->name].numBreaks == 0) {
-          curr->type = unreachable;
+          curr->type = Type::unreachable;
         } else {
           return; // did not turn
         }
       } else if (auto* iff = curr->dynCast<If>()) {
         // may not be unreachable if just one side is
         iff->finalize();
-        if (curr->type != unreachable) {
+        if (curr->type != Type::unreachable) {
           return; // did not turn
         }
       } else if (auto* tryy = curr->dynCast<Try>()) {
         tryy->finalize();
-        if (curr->type != unreachable) {
+        if (curr->type != Type::unreachable) {
           return; // did not turn
         }
       } else {
-        curr->type = unreachable;
+        curr->type = Type::unreachable;
       }
     }
   }
@@ -276,7 +276,7 @@ struct TypeUpdater
   }
 
   void makeBlockUnreachableIfNoFallThrough(Block* curr) {
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       return; // no change possible
     }
     if (!curr->list.empty() && curr->list.back()->type.isConcrete()) {
@@ -284,9 +284,9 @@ struct TypeUpdater
       return;
     }
     for (auto* child : curr->list) {
-      if (child->type == unreachable) {
+      if (child->type == Type::unreachable) {
         // no fallthrough, and an unreachable, => this block is now unreachable
-        changeTypeTo(curr, unreachable);
+        changeTypeTo(curr, Type::unreachable);
         return;
       }
     }
@@ -300,7 +300,7 @@ struct TypeUpdater
       return; // nothing concrete to change to unreachable
     }
     curr->finalize();
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       propagateTypesUp(curr);
     }
   }
@@ -310,7 +310,7 @@ struct TypeUpdater
       return; // nothing concrete to change to unreachable
     }
     curr->finalize();
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       propagateTypesUp(curr);
     }
   }
diff --git a/src/ir/utils.h b/src/ir/utils.h
index 9bd3c9e0b..b7c5b9cba 100644
--- a/src/ir/utils.h
+++ b/src/ir/utils.h
@@ -281,7 +281,7 @@ struct AutoDrop : public WalkerPass<ExpressionStackWalker<AutoDrop>> {
     }
     if (maybeDrop(curr->list.back())) {
       reFinalize();
-      assert(curr->type == none || curr->type == unreachable);
+      assert(curr->type == Type::none || curr->type == Type::unreachable);
     }
   }
 
@@ -297,7 +297,7 @@ struct AutoDrop : public WalkerPass<ExpressionStackWalker<AutoDrop>> {
     }
     if (acted) {
       reFinalize();
-      assert(curr->type == none);
+      assert(curr->type == Type::none);
     }
   }
 
@@ -323,20 +323,21 @@ struct I64Utilities {
   };
 
   static Expression* recreateI64(Builder& builder, Index low, Index high) {
-    return recreateI64(
-      builder, builder.makeLocalGet(low, i32), builder.makeLocalGet(high, i32));
+    return recreateI64(builder,
+                       builder.makeLocalGet(low, Type::i32),
+                       builder.makeLocalGet(high, Type::i32));
   };
 
   static Expression* getI64High(Builder& builder, Index index) {
     return builder.makeUnary(
       WrapInt64,
       builder.makeBinary(ShrUInt64,
-                         builder.makeLocalGet(index, i64),
+                         builder.makeLocalGet(index, Type::i64),
                          builder.makeConst(Literal(int64_t(32)))));
   }
 
   static Expression* getI64Low(Builder& builder, Index index) {
-    return builder.makeUnary(WrapInt64, builder.makeLocalGet(index, i64));
+    return builder.makeUnary(WrapInt64, builder.makeLocalGet(index, Type::i64));
   }
 };
 
diff --git a/src/parsing.h b/src/parsing.h
index d64236df3..a75e953b4 100644
--- a/src/parsing.h
+++ b/src/parsing.h
@@ -85,10 +85,10 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
   if (type.isFloat()) {
     if (s == _INFINITY) {
       switch (type) {
-        case f32:
+        case Type::f32:
           ret->value = Literal(std::numeric_limits<float>::infinity());
           break;
-        case f64:
+        case Type::f64:
           ret->value = Literal(std::numeric_limits<double>::infinity());
           break;
         default:
@@ -99,10 +99,10 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
     }
     if (s == NEG_INFINITY) {
       switch (type) {
-        case f32:
+        case Type::f32:
           ret->value = Literal(-std::numeric_limits<float>::infinity());
           break;
-        case f64:
+        case Type::f64:
           ret->value = Literal(-std::numeric_limits<double>::infinity());
           break;
         default:
@@ -113,10 +113,10 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
     }
     if (s == _NAN) {
       switch (type) {
-        case f32:
+        case Type::f32:
           ret->value = Literal(float(std::nan("")));
           break;
-        case f64:
+        case Type::f64:
           ret->value = Literal(double(std::nan("")));
           break;
         default:
@@ -138,7 +138,7 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
         throw ParseException("bad nan input");
       }
       switch (type) {
-        case f32: {
+        case Type::f32: {
           uint32_t pattern;
           if (modifier) {
             std::istringstream istr(modifier);
@@ -159,7 +159,7 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
           ret->value = Literal(pattern).castToF32();
           break;
         }
-        case f64: {
+        case Type::f64: {
           uint64_t pattern;
           if (modifier) {
             std::istringstream istr(modifier);
@@ -188,10 +188,10 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
     }
     if (s == NEG_NAN) {
       switch (type) {
-        case f32:
+        case Type::f32:
           ret->value = Literal(float(-std::nan("")));
           break;
-        case f64:
+        case Type::f64:
           ret->value = Literal(double(-std::nan("")));
           break;
         default:
@@ -202,7 +202,7 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
     }
   }
   switch (type) {
-    case i32: {
+    case Type::i32: {
       if ((str[0] == '0' && str[1] == 'x') ||
           (str[0] == '-' && str[1] == '0' && str[2] == 'x')) {
         bool negative = str[0] == '-';
@@ -227,7 +227,7 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
       }
       break;
     }
-    case i64: {
+    case Type::i64: {
       if ((str[0] == '0' && str[1] == 'x') ||
           (str[0] == '-' && str[1] == '0' && str[2] == 'x')) {
         bool negative = str[0] == '-';
@@ -252,24 +252,24 @@ parseConst(cashew::IString s, Type type, MixedArena& allocator) {
       }
       break;
     }
-    case f32: {
+    case Type::f32: {
       char* end;
       ret->value = Literal(strtof(str, &end));
       break;
     }
-    case f64: {
+    case Type::f64: {
       char* end;
       ret->value = Literal(strtod(str, &end));
       break;
     }
-    case v128:
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
+    case Type::v128:
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
       WASM_UNREACHABLE("unexpected const type");
-    case none:
-    case unreachable: {
+    case Type::none:
+    case Type::unreachable: {
       return nullptr;
     }
   }
diff --git a/src/passes/AlignmentLowering.cpp b/src/passes/AlignmentLowering.cpp
index d659fcb69..18fe46398 100644
--- a/src/passes/AlignmentLowering.cpp
+++ b/src/passes/AlignmentLowering.cpp
@@ -32,26 +32,31 @@ struct AlignmentLowering : public WalkerPass<PostWalker<AlignmentLowering>> {
       return;
     }
     Builder builder(*getModule());
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       replaceCurrent(curr->ptr);
       return;
     }
-    assert(curr->type == i32); // TODO: i64, f32, f64
-    auto temp = builder.addVar(getFunction(), i32);
+    assert(curr->type == Type::i32); // TODO: i64, f32, f64
+    auto temp = builder.addVar(getFunction(), Type::i32);
     Expression* ret;
     if (curr->bytes == 2) {
       ret = builder.makeBinary(
         OrInt32,
-        builder.makeLoad(
-          1, false, curr->offset, 1, builder.makeLocalGet(temp, i32), i32),
-        builder.makeBinary(ShlInt32,
-                           builder.makeLoad(1,
-                                            false,
-                                            curr->offset + 1,
-                                            1,
-                                            builder.makeLocalGet(temp, i32),
-                                            i32),
-                           builder.makeConst(Literal(int32_t(8)))));
+        builder.makeLoad(1,
+                         false,
+                         curr->offset,
+                         1,
+                         builder.makeLocalGet(temp, Type::i32),
+                         Type::i32),
+        builder.makeBinary(
+          ShlInt32,
+          builder.makeLoad(1,
+                           false,
+                           curr->offset + 1,
+                           1,
+                           builder.makeLocalGet(temp, Type::i32),
+                           Type::i32),
+          builder.makeConst(Literal(int32_t(8)))));
       if (curr->signed_) {
         ret = Bits::makeSignExt(ret, 2, *getModule());
       }
@@ -61,47 +66,59 @@ struct AlignmentLowering : public WalkerPass<PostWalker<AlignmentLowering>> {
           OrInt32,
           builder.makeBinary(
             OrInt32,
-            builder.makeLoad(
-              1, false, curr->offset, 1, builder.makeLocalGet(temp, i32), i32),
-            builder.makeBinary(ShlInt32,
-                               builder.makeLoad(1,
-                                                false,
-                                                curr->offset + 1,
-                                                1,
-                                                builder.makeLocalGet(temp, i32),
-                                                i32),
-                               builder.makeConst(Literal(int32_t(8))))),
+            builder.makeLoad(1,
+                             false,
+                             curr->offset,
+                             1,
+                             builder.makeLocalGet(temp, Type::i32),
+                             Type::i32),
+            builder.makeBinary(
+              ShlInt32,
+              builder.makeLoad(1,
+                               false,
+                               curr->offset + 1,
+                               1,
+                               builder.makeLocalGet(temp, Type::i32),
+                               Type::i32),
+              builder.makeConst(Literal(int32_t(8))))),
           builder.makeBinary(
             OrInt32,
-            builder.makeBinary(ShlInt32,
-                               builder.makeLoad(1,
-                                                false,
-                                                curr->offset + 2,
-                                                1,
-                                                builder.makeLocalGet(temp, i32),
-                                                i32),
-                               builder.makeConst(Literal(int32_t(16)))),
-            builder.makeBinary(ShlInt32,
-                               builder.makeLoad(1,
-                                                false,
-                                                curr->offset + 3,
-                                                1,
-                                                builder.makeLocalGet(temp, i32),
-                                                i32),
-                               builder.makeConst(Literal(int32_t(24))))));
+            builder.makeBinary(
+              ShlInt32,
+              builder.makeLoad(1,
+                               false,
+                               curr->offset + 2,
+                               1,
+                               builder.makeLocalGet(temp, Type::i32),
+                               Type::i32),
+              builder.makeConst(Literal(int32_t(16)))),
+            builder.makeBinary(
+              ShlInt32,
+              builder.makeLoad(1,
+                               false,
+                               curr->offset + 3,
+                               1,
+                               builder.makeLocalGet(temp, Type::i32),
+                               Type::i32),
+              builder.makeConst(Literal(int32_t(24))))));
       } else if (curr->align == 2) {
         ret = builder.makeBinary(
           OrInt32,
-          builder.makeLoad(
-            2, false, curr->offset, 2, builder.makeLocalGet(temp, i32), i32),
-          builder.makeBinary(ShlInt32,
-                             builder.makeLoad(2,
-                                              false,
-                                              curr->offset + 2,
-                                              2,
-                                              builder.makeLocalGet(temp, i32),
-                                              i32),
-                             builder.makeConst(Literal(int32_t(16)))));
+          builder.makeLoad(2,
+                           false,
+                           curr->offset,
+                           2,
+                           builder.makeLocalGet(temp, Type::i32),
+                           Type::i32),
+          builder.makeBinary(
+            ShlInt32,
+            builder.makeLoad(2,
+                             false,
+                             curr->offset + 2,
+                             2,
+                             builder.makeLocalGet(temp, Type::i32),
+                             Type::i32),
+            builder.makeConst(Literal(int32_t(16)))));
       } else {
         WASM_UNREACHABLE("invalid alignment");
       }
@@ -117,14 +134,14 @@ struct AlignmentLowering : public WalkerPass<PostWalker<AlignmentLowering>> {
       return;
     }
     Builder builder(*getModule());
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       replaceCurrent(builder.makeBlock(
         {builder.makeDrop(curr->ptr), builder.makeDrop(curr->value)}));
       return;
     }
-    assert(curr->value->type == i32); // TODO: i64, f32, f64
-    auto tempPtr = builder.addVar(getFunction(), i32);
-    auto tempValue = builder.addVar(getFunction(), i32);
+    assert(curr->value->type == Type::i32); // TODO: i64, f32, f64
+    auto tempPtr = builder.addVar(getFunction(), Type::i32);
+    auto tempValue = builder.addVar(getFunction(), Type::i32);
     auto* block =
       builder.makeBlock({builder.makeLocalSet(tempPtr, curr->ptr),
                          builder.makeLocalSet(tempValue, curr->value)});
@@ -133,71 +150,71 @@ struct AlignmentLowering : public WalkerPass<PostWalker<AlignmentLowering>> {
         builder.makeStore(1,
                           curr->offset,
                           1,
-                          builder.makeLocalGet(tempPtr, i32),
-                          builder.makeLocalGet(tempValue, i32),
-                          i32));
+                          builder.makeLocalGet(tempPtr, Type::i32),
+                          builder.makeLocalGet(tempValue, Type::i32),
+                          Type::i32));
       block->list.push_back(builder.makeStore(
         1,
         curr->offset + 1,
         1,
-        builder.makeLocalGet(tempPtr, i32),
+        builder.makeLocalGet(tempPtr, Type::i32),
         builder.makeBinary(ShrUInt32,
-                           builder.makeLocalGet(tempValue, i32),
+                           builder.makeLocalGet(tempValue, Type::i32),
                            builder.makeConst(Literal(int32_t(8)))),
-        i32));
+        Type::i32));
     } else if (curr->bytes == 4) {
       if (curr->align == 1) {
         block->list.push_back(
           builder.makeStore(1,
                             curr->offset,
                             1,
-                            builder.makeLocalGet(tempPtr, i32),
-                            builder.makeLocalGet(tempValue, i32),
-                            i32));
+                            builder.makeLocalGet(tempPtr, Type::i32),
+                            builder.makeLocalGet(tempValue, Type::i32),
+                            Type::i32));
         block->list.push_back(builder.makeStore(
           1,
           curr->offset + 1,
           1,
-          builder.makeLocalGet(tempPtr, i32),
+          builder.makeLocalGet(tempPtr, Type::i32),
           builder.makeBinary(ShrUInt32,
-                             builder.makeLocalGet(tempValue, i32),
+                             builder.makeLocalGet(tempValue, Type::i32),
                              builder.makeConst(Literal(int32_t(8)))),
-          i32));
+          Type::i32));
         block->list.push_back(builder.makeStore(
           1,
           curr->offset + 2,
           1,
-          builder.makeLocalGet(tempPtr, i32),
+          builder.makeLocalGet(tempPtr, Type::i32),
           builder.makeBinary(ShrUInt32,
-                             builder.makeLocalGet(tempValue, i32),
+                             builder.makeLocalGet(tempValue, Type::i32),
                              builder.makeConst(Literal(int32_t(16)))),
-          i32));
+          Type::i32));
         block->list.push_back(builder.makeStore(
           1,
           curr->offset + 3,
           1,
-          builder.makeLocalGet(tempPtr, i32),
+          builder.makeLocalGet(tempPtr, Type::i32),
           builder.makeBinary(ShrUInt32,
-                             builder.makeLocalGet(tempValue, i32),
+                             builder.makeLocalGet(tempValue, Type::i32),
                              builder.makeConst(Literal(int32_t(24)))),
-          i32));
+          Type::i32));
       } else if (curr->align == 2) {
         block->list.push_back(
           builder.makeStore(2,
                             curr->offset,
                             2,
-                            builder.makeLocalGet(tempPtr, i32),
-                            builder.makeLocalGet(tempValue, i32),
-                            i32));
+                            builder.makeLocalGet(tempPtr, Type::i32),
+                            builder.makeLocalGet(tempValue, Type::i32),
+                            Type::i32));
         block->list.push_back(builder.makeStore(
           2,
           curr->offset + 2,
           2,
-          builder.makeLocalGet(tempPtr, i32),
+          builder.makeLocalGet(tempPtr, Type::i32),
           builder.makeBinary(ShrUInt32,
-                             builder.makeLocalGet(tempValue, i32),
+                             builder.makeLocalGet(tempValue, Type::i32),
                              builder.makeConst(Literal(int32_t(16)))),
-          i32));
+          Type::i32));
       } else {
         WASM_UNREACHABLE("invalid alignment");
       }
diff --git a/src/passes/Asyncify.cpp b/src/passes/Asyncify.cpp
index 8f929d9fe..b7e8c90e0 100644
--- a/src/passes/Asyncify.cpp
+++ b/src/passes/Asyncify.cpp
@@ -298,10 +298,10 @@ class GlobalHelper {
 
 public:
   GlobalHelper(Module& module) : module(module) {
-    map[i32] = "asyncify_fake_call_global_i32";
-    map[i64] = "asyncify_fake_call_global_i64";
-    map[f32] = "asyncify_fake_call_global_f32";
-    map[f64] = "asyncify_fake_call_global_f64";
+    map[Type::i32] = "asyncify_fake_call_global_i32";
+    map[Type::i64] = "asyncify_fake_call_global_i64";
+    map[Type::f32] = "asyncify_fake_call_global_f32";
+    map[Type::f64] = "asyncify_fake_call_global_f64";
     Builder builder(module);
     for (auto& pair : map) {
       auto type = pair.first;
@@ -326,7 +326,7 @@ public:
     if (iter != rev.end()) {
       return iter->second;
     }
-    return none;
+    return Type::none;
   }
 
 private:
@@ -647,8 +647,8 @@ public:
                     false,
                     int32_t(DataOffset::BStackPos),
                     4,
-                    makeGlobalGet(ASYNCIFY_DATA, i32),
-                    i32);
+                    makeGlobalGet(ASYNCIFY_DATA, Type::i32),
+                    Type::i32);
   }
 
   Expression* makeIncStackPos(int32_t by) {
@@ -659,14 +659,14 @@ public:
       4,
       int32_t(DataOffset::BStackPos),
       4,
-      makeGlobalGet(ASYNCIFY_DATA, i32),
+      makeGlobalGet(ASYNCIFY_DATA, Type::i32),
       makeBinary(AddInt32, makeGetStackPos(), makeConst(Literal(by))),
-      i32);
+      Type::i32);
   }
 
   Expression* makeStateCheck(State value) {
     return makeBinary(EqInt32,
-                      makeGlobalGet(ASYNCIFY_STATE, i32),
+                      makeGlobalGet(ASYNCIFY_STATE, Type::i32),
                       makeConst(Literal(int32_t(value))));
   }
 
@@ -810,11 +810,11 @@ private:
         iff->finalize();
         return iff;
       }
-      auto conditionTemp = builder->addVar(func, i32);
+      auto conditionTemp = builder->addVar(func, Type::i32);
       // TODO: can avoid pre if the condition is a get or a const
       auto* pre =
         makeMaybeSkip(builder->makeLocalSet(conditionTemp, iff->condition));
-      iff->condition = builder->makeLocalGet(conditionTemp, i32);
+      iff->condition = builder->makeLocalGet(conditionTemp, Type::i32);
       iff->condition = builder->makeBinary(
         OrInt32, iff->condition, builder->makeStateCheck(State::Rewinding));
       iff->ifTrue = process(iff->ifTrue);
@@ -826,7 +826,7 @@ private:
         builder->makeBinary(
           OrInt32,
           builder->makeUnary(EqZInt32,
-                             builder->makeLocalGet(conditionTemp, i32)),
+                             builder->makeLocalGet(conditionTemp, Type::i32)),
           builder->makeStateCheck(State::Rewinding)),
         process(otherArm));
       otherIf->finalize();
@@ -853,7 +853,7 @@ private:
     // TODO: stop doing this after code can no longer reach a call that may
     //       change the state
     assert(doesCall(curr));
-    assert(curr->type == none);
+    assert(curr->type == Type::none);
     // The case of a set is tricky: we must *not* execute the set when
     // unwinding, since at that point we have a fake value for the return,
     // and if we applied it to the local, it would end up saved and then
@@ -893,8 +893,9 @@ private:
     // it when we add its contents, later.)
     return builder->makeIf(
       builder->makeStateCheck(State::Unwinding),
-      builder->makeCall(
-        ASYNCIFY_UNWIND, {builder->makeConst(Literal(int32_t(index)))}, none),
+      builder->makeCall(ASYNCIFY_UNWIND,
+                        {builder->makeConst(Literal(int32_t(index)))},
+                        Type::none),
       ifNotUnwinding);
   }
 
@@ -903,13 +904,13 @@ private:
     // don't want it to be seen by asyncify itself.
     return builder->makeCall(ASYNCIFY_CHECK_CALL_INDEX,
                              {builder->makeConst(Literal(int32_t(index)))},
-                             i32);
+                             Type::i32);
   }
 
   Expression* makeCallIndexPop() {
     // Emit an intrinsic for this, as we store the index into a local, and
     // don't want it to be seen by asyncify itself.
-    return builder->makeCall(ASYNCIFY_GET_CALL_INDEX, {}, none);
+    return builder->makeCall(ASYNCIFY_GET_CALL_INDEX, {}, Type::none);
   }
 
   // Given a function that is not instrumented - because we proved it doesn't
@@ -921,11 +922,11 @@ private:
   // That is, if in an uninstrumented function, a sleep should not begin
   // from any call.
   void addAssertsInNonInstrumented(Function* func) {
-    auto oldState = builder->addVar(func, i32);
+    auto oldState = builder->addVar(func, Type::i32);
     // Add a check at the function entry.
     func->body = builder->makeSequence(
       builder->makeLocalSet(oldState,
-                            builder->makeGlobalGet(ASYNCIFY_STATE, i32)),
+                            builder->makeGlobalGet(ASYNCIFY_STATE, Type::i32)),
       func->body);
     // Add a check around every call.
     struct Walker : PostWalker<Walker> {
@@ -944,8 +945,8 @@ private:
       void handleCall(Expression* call) {
         auto* check = builder->makeIf(
           builder->makeBinary(NeInt32,
-                              builder->makeGlobalGet(ASYNCIFY_STATE, i32),
-                              builder->makeLocalGet(oldState, i32)),
+                              builder->makeGlobalGet(ASYNCIFY_STATE, Type::i32),
+                              builder->makeLocalGet(oldState, Type::i32)),
           builder->makeUnreachable());
         Expression* rep;
         if (call->type.isConcrete()) {
@@ -991,11 +992,12 @@ struct AsyncifyLocals : public WalkerPass<PostWalker<AsyncifyLocals>> {
         builder->makeIncStackPos(-4),
         builder->makeLocalSet(
           rewindIndex,
-          builder->makeLoad(4, false, 0, 4, builder->makeGetStackPos(), i32))));
+          builder->makeLoad(
+            4, false, 0, 4, builder->makeGetStackPos(), Type::i32))));
     } else if (curr->target == ASYNCIFY_CHECK_CALL_INDEX) {
       replaceCurrent(builder->makeBinary(
         EqInt32,
-        builder->makeLocalGet(rewindIndex, i32),
+        builder->makeLocalGet(rewindIndex, Type::i32),
         builder->makeConst(
           Literal(int32_t(curr->operands[0]->cast<Const>()->value.geti32())))));
     }
@@ -1003,7 +1005,7 @@ struct AsyncifyLocals : public WalkerPass<PostWalker<AsyncifyLocals>> {
 
   void visitGlobalSet(GlobalSet* curr) {
     auto type = analyzer->globals.getTypeOrNone(curr->name);
-    if (type != none) {
+    if (type != Type::none) {
       replaceCurrent(
         builder->makeLocalSet(getFakeCallLocal(type), curr->value));
     }
@@ -1011,7 +1013,7 @@ struct AsyncifyLocals : public WalkerPass<PostWalker<AsyncifyLocals>> {
 
   void visitGlobalGet(GlobalGet* curr) {
     auto type = analyzer->globals.getTypeOrNone(curr->name);
-    if (type != none) {
+    if (type != Type::none) {
       replaceCurrent(builder->makeLocalGet(getFakeCallLocal(type), type));
     }
   }
@@ -1038,8 +1040,8 @@ struct AsyncifyLocals : public WalkerPass<PostWalker<AsyncifyLocals>> {
     // well as saving the locals.
     // An index is needed for getting the unwinding and rewinding call indexes
     // around TODO: can this be the same index?
-    auto unwindIndex = builder->addVar(func, i32);
-    rewindIndex = builder->addVar(func, i32);
+    auto unwindIndex = builder->addVar(func, Type::i32);
+    rewindIndex = builder->addVar(func, Type::i32);
     // Rewrite the function body.
     builder = make_unique<AsyncifyBuilder>(*getModule());
     walk(func->body);
@@ -1095,7 +1097,7 @@ private:
     }
     auto* block = builder->makeBlock();
     block->list.push_back(builder->makeIncStackPos(-total));
-    auto tempIndex = builder->addVar(func, i32);
+    auto tempIndex = builder->addVar(func, Type::i32);
     block->list.push_back(
       builder->makeLocalSet(tempIndex, builder->makeGetStackPos()));
     Index offset = 0;
@@ -1110,7 +1112,7 @@ private:
                           true,
                           offset,
                           STACK_ALIGN,
-                          builder->makeLocalGet(tempIndex, i32),
+                          builder->makeLocalGet(tempIndex, Type::i32),
                           type)));
       offset += size;
     }
@@ -1124,7 +1126,7 @@ private:
     }
     auto* func = getFunction();
     auto* block = builder->makeBlock();
-    auto tempIndex = builder->addVar(func, i32);
+    auto tempIndex = builder->addVar(func, Type::i32);
     block->list.push_back(
       builder->makeLocalSet(tempIndex, builder->makeGetStackPos()));
     Index offset = 0;
@@ -1137,7 +1139,7 @@ private:
         builder->makeStore(size,
                            offset,
                            STACK_ALIGN,
-                           builder->makeLocalGet(tempIndex, i32),
+                           builder->makeLocalGet(tempIndex, Type::i32),
                            builder->makeLocalGet(i, type),
                            type));
       offset += size;
@@ -1154,8 +1156,8 @@ private:
                          0,
                          4,
                          builder->makeGetStackPos(),
-                         builder->makeLocalGet(tempIndex, i32),
-                         i32),
+                         builder->makeLocalGet(tempIndex, Type::i32),
+                         Type::i32),
       builder->makeIncStackPos(4));
   }
 };
@@ -1281,11 +1283,11 @@ private:
   void addGlobals(Module* module) {
     Builder builder(*module);
     module->addGlobal(builder.makeGlobal(ASYNCIFY_STATE,
-                                         i32,
+                                         Type::i32,
                                          builder.makeConst(Literal(int32_t(0))),
                                          Builder::Mutable));
     module->addGlobal(builder.makeGlobal(ASYNCIFY_DATA,
-                                         i32,
+                                         Type::i32,
                                          builder.makeConst(Literal(int32_t(0))),
                                          Builder::Mutable));
   }
@@ -1295,14 +1297,14 @@ private:
     auto makeFunction = [&](Name name, bool setData, State state) {
       std::vector<Type> params;
       if (setData) {
-        params.push_back(i32);
+        params.push_back(Type::i32);
       }
       auto* body = builder.makeBlock();
       body->list.push_back(builder.makeGlobalSet(
         ASYNCIFY_STATE, builder.makeConst(Literal(int32_t(state)))));
       if (setData) {
-        body->list.push_back(
-          builder.makeGlobalSet(ASYNCIFY_DATA, builder.makeLocalGet(0, i32)));
+        body->list.push_back(builder.makeGlobalSet(
+          ASYNCIFY_DATA, builder.makeLocalGet(0, Type::i32)));
       }
       // Verify the data is valid.
       auto* stackPos =
@@ -1310,15 +1312,15 @@ private:
                          false,
                          int32_t(DataOffset::BStackPos),
                          4,
-                         builder.makeGlobalGet(ASYNCIFY_DATA, i32),
-                         i32);
+                         builder.makeGlobalGet(ASYNCIFY_DATA, Type::i32),
+                         Type::i32);
       auto* stackEnd =
         builder.makeLoad(4,
                          false,
                          int32_t(DataOffset::BStackEnd),
                          4,
-                         builder.makeGlobalGet(ASYNCIFY_DATA, i32),
-                         i32);
+                         builder.makeGlobalGet(ASYNCIFY_DATA, Type::i32),
+                         Type::i32);
       body->list.push_back(
         builder.makeIf(builder.makeBinary(GtUInt32, stackPos, stackEnd),
                        builder.makeUnreachable()));
diff --git a/src/passes/AvoidReinterprets.cpp b/src/passes/AvoidReinterprets.cpp
index f1b3d96d8..4df75dd15 100644
--- a/src/passes/AvoidReinterprets.cpp
+++ b/src/passes/AvoidReinterprets.cpp
@@ -115,7 +115,7 @@ struct AvoidReinterprets : public WalkerPass<PostWalker<AvoidReinterprets>> {
       auto& info = pair.second;
       if (info.reinterpreted && canReplaceWithReinterpret(load)) {
         // We should use another load here, to avoid reinterprets.
-        info.ptrLocal = Builder::addVar(func, i32);
+        info.ptrLocal = Builder::addVar(func, Type::i32);
         info.reinterpretedLocal =
           Builder::addVar(func, load->type.reinterpret());
       } else {
@@ -165,7 +165,7 @@ struct AvoidReinterprets : public WalkerPass<PostWalker<AvoidReinterprets>> {
           auto& info = iter->second;
           Builder builder(*module);
           auto* ptr = curr->ptr;
-          curr->ptr = builder.makeLocalGet(info.ptrLocal, i32);
+          curr->ptr = builder.makeLocalGet(info.ptrLocal, Type::i32);
           // Note that the other load can have its sign set to false - if the
           // original were an integer, the other is a float anyhow; and if
           // original were a float, we don't know what sign to use.
@@ -173,8 +173,8 @@ struct AvoidReinterprets : public WalkerPass<PostWalker<AvoidReinterprets>> {
             {builder.makeLocalSet(info.ptrLocal, ptr),
              builder.makeLocalSet(
                info.reinterpretedLocal,
-               makeReinterpretedLoad(curr,
-                                     builder.makeLocalGet(info.ptrLocal, i32))),
+               makeReinterpretedLoad(
+                 curr, builder.makeLocalGet(info.ptrLocal, Type::i32))),
              curr}));
         }
       }
diff --git a/src/passes/CodeFolding.cpp b/src/passes/CodeFolding.cpp
index 947e64715..9b6e1143d 100644
--- a/src/passes/CodeFolding.cpp
+++ b/src/passes/CodeFolding.cpp
@@ -201,7 +201,7 @@ struct CodeFolding : public WalkerPass<ControlFlowWalker<CodeFolding>> {
     // see if there is a fallthrough
     bool hasFallthrough = true;
     for (auto* child : curr->list) {
-      if (child->type == unreachable) {
+      if (child->type == Type::unreachable) {
         hasFallthrough = false;
       }
     }
@@ -685,12 +685,12 @@ private:
     auto* old = getFunction()->body;
     auto* inner = builder.makeBlock();
     inner->name = innerName;
-    if (old->type == unreachable) {
+    if (old->type == Type::unreachable) {
       // the old body is not flowed out of anyhow, so just put it there
       inner->list.push_back(old);
     } else {
       // otherwise, we must not flow out to the merged code
-      if (old->type == none) {
+      if (old->type == Type::none) {
         inner->list.push_back(old);
         inner->list.push_back(builder.makeReturn());
       } else {
@@ -703,7 +703,7 @@ private:
         if (toplevel) {
           toplevel->finalize();
         }
-        if (old->type != unreachable) {
+        if (old->type != Type::unreachable) {
           inner->list.push_back(builder.makeReturn(old));
         } else {
           inner->list.push_back(old);
diff --git a/src/passes/ConstHoisting.cpp b/src/passes/ConstHoisting.cpp
index 4e8cd9910..6c79c4215 100644
--- a/src/passes/ConstHoisting.cpp
+++ b/src/passes/ConstHoisting.cpp
@@ -78,29 +78,29 @@ private:
     // measure the size of the constant
     Index size = 0;
     switch (value.type) {
-      case i32: {
+      case Type::i32: {
         size = getWrittenSize(S32LEB(value.geti32()));
         break;
       }
-      case i64: {
+      case Type::i64: {
         size = getWrittenSize(S64LEB(value.geti64()));
         break;
       }
-      case f32:
-      case f64: {
+      case Type::f32:
+      case Type::f64: {
         size = value.type.getByteSize();
         break;
       }
-      // not implemented yet
-      case v128:
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref: {
+        // not implemented yet
+      case Type::v128:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref: {
         return false;
       }
-      case none:
-      case unreachable:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
     // compute the benefit, of replacing the uses with
diff --git a/src/passes/DeadArgumentElimination.cpp b/src/passes/DeadArgumentElimination.cpp
index 4395fc780..43ebc6721 100644
--- a/src/passes/DeadArgumentElimination.cpp
+++ b/src/passes/DeadArgumentElimination.cpp
@@ -294,21 +294,21 @@ struct DAE : public Pass {
           assert(call->operands.size() == numParams);
           auto* operand = call->operands[i];
           if (auto* c = operand->dynCast<Const>()) {
-            if (value.type == none) {
+            if (value.type == Type::none) {
               // This is the first value seen.
               value = c->value;
             } else if (value != c->value) {
               // Not identical, give up
-              value.type = none;
+              value.type = Type::none;
               break;
             }
           } else {
             // Not a constant, give up
-            value.type = none;
+            value.type = Type::none;
             break;
           }
         }
-        if (value.type != none) {
+        if (value.type != Type::none) {
           // Success! We can just apply the constant in the function, which
           // makes the parameter value unused, which lets us remove it later.
           Builder builder(*module);
@@ -466,8 +466,8 @@ private:
       Expression** location = iter->second;
       *location = call;
       // Update the call's type.
-      if (call->type != unreachable) {
-        call->type = none;
+      if (call->type != Type::unreachable) {
+        call->type = Type::none;
       }
     }
   }
diff --git a/src/passes/DeadCodeElimination.cpp b/src/passes/DeadCodeElimination.cpp
index 7d5385a83..ac984f6cb 100644
--- a/src/passes/DeadCodeElimination.cpp
+++ b/src/passes/DeadCodeElimination.cpp
@@ -82,10 +82,14 @@ struct DeadCodeElimination
   }
 
   // if a child exists and is unreachable, we can replace ourselves with it
-  bool isDead(Expression* child) { return child && child->type == unreachable; }
+  bool isDead(Expression* child) {
+    return child && child->type == Type::unreachable;
+  }
 
   // a similar check, assumes the child exists
-  bool isUnreachable(Expression* child) { return child->type == unreachable; }
+  bool isUnreachable(Expression* child) {
+    return child->type == Type::unreachable;
+  }
 
   // things that stop control flow
 
@@ -170,7 +174,7 @@ struct DeadCodeElimination
     if (!reachable && list.size() > 1) {
       // to do here: nothing to remove after it)
       for (Index i = 0; i < list.size() - 1; i++) {
-        if (list[i]->type == unreachable) {
+        if (list[i]->type == Type::unreachable) {
           list.resize(i + 1);
           break;
         }
@@ -393,7 +397,7 @@ struct DeadCodeElimination
 
   // we don't need to drop unreachable nodes
   Expression* drop(Expression* toDrop) {
-    if (toDrop->type == unreachable) {
+    if (toDrop->type == Type::unreachable) {
       return toDrop;
     }
     return Builder(*getModule()).makeDrop(toDrop);
diff --git a/src/passes/Flatten.cpp b/src/passes/Flatten.cpp
index fda8e3f80..13aa985aa 100644
--- a/src/passes/Flatten.cpp
+++ b/src/passes/Flatten.cpp
@@ -105,7 +105,7 @@ struct Flatten
           if (last->type.isConcrete()) {
             last = builder.makeLocalSet(temp, last);
           }
-          block->finalize(none);
+          block->finalize(Type::none);
           // and we leave just a get of the value
           auto* rep = builder.makeLocalGet(temp, type);
           replaceCurrent(rep);
@@ -113,7 +113,7 @@ struct Flatten
           ourPreludes.push_back(block);
         }
         // the block now has no return value, and may have become unreachable
-        block->finalize(none);
+        block->finalize(Type::none);
 
       } else if (auto* iff = curr->dynCast<If>()) {
         // condition preludes go before the entire if
@@ -160,7 +160,7 @@ struct Flatten
           rep = builder.makeLocalGet(temp, type);
           // the whole if is now a prelude
           ourPreludes.push_back(loop);
-          loop->type = none;
+          loop->type = Type::none;
         }
         loop->body = getPreludesWithExpression(originalBody, loop->body);
         loop->finalize();
@@ -181,7 +181,7 @@ struct Flatten
       if (auto* set = curr->dynCast<LocalSet>()) {
         if (set->isTee()) {
           // we disallow local.tee
-          if (set->value->type == unreachable) {
+          if (set->value->type == Type::unreachable) {
             replaceCurrent(set->value); // trivial, no set happens
           } else {
             // use a set in a prelude + a get
@@ -234,14 +234,14 @@ struct Flatten
               if (br->type.isConcrete()) {
                 replaceCurrent(builder.makeLocalGet(temp, type));
               } else {
-                assert(br->type == unreachable);
+                assert(br->type == Type::unreachable);
                 replaceCurrent(builder.makeUnreachable());
               }
             }
             br->value = nullptr;
             br->finalize();
           } else {
-            assert(type == unreachable);
+            assert(type == Type::unreachable);
             // we don't need the br at all
             replaceCurrent(br->value);
           }
@@ -264,7 +264,7 @@ struct Flatten
             sw->value = nullptr;
             sw->finalize();
           } else {
-            assert(type == unreachable);
+            assert(type == Type::unreachable);
             // we don't need the br at all
             replaceCurrent(sw->value);
           }
@@ -277,7 +277,7 @@ struct Flatten
     curr = getCurrent(); // we may have replaced it
     // we have changed children
     ReFinalizeNode().visit(curr);
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       ourPreludes.push_back(curr);
       replaceCurrent(builder.makeUnreachable());
     } else if (curr->type.isConcrete()) {
diff --git a/src/passes/FuncCastEmulation.cpp b/src/passes/FuncCastEmulation.cpp
index 9d5109a83..09c87c212 100644
--- a/src/passes/FuncCastEmulation.cpp
+++ b/src/passes/FuncCastEmulation.cpp
@@ -45,38 +45,39 @@ static const int NUM_PARAMS = 16;
 static Expression* toABI(Expression* value, Module* module) {
   Builder builder(*module);
   switch (value->type) {
-    case i32: {
+    case Type::i32: {
       value = builder.makeUnary(ExtendUInt32, value);
       break;
     }
-    case i64: {
+    case Type::i64: {
       // already good
       break;
     }
-    case f32: {
+    case Type::f32: {
       value = builder.makeUnary(ExtendUInt32,
                                 builder.makeUnary(ReinterpretFloat32, value));
       break;
     }
-    case f64: {
+    case Type::f64: {
       value = builder.makeUnary(ReinterpretFloat64, value);
       break;
     }
-    case v128: {
+    case Type::v128: {
       WASM_UNREACHABLE("v128 not implemented yet");
     }
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref: {
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref: {
       WASM_UNREACHABLE("reference types cannot be converted to i64");
     }
-    case none: {
+    case Type::none: {
       // the value is none, but we need a value here
-      value = builder.makeSequence(value, LiteralUtils::makeZero(i64, *module));
+      value =
+        builder.makeSequence(value, LiteralUtils::makeZero(Type::i64, *module));
       break;
     }
-    case unreachable: {
+    case Type::unreachable: {
       // can leave it, the call isn't taken anyhow
       break;
     }
@@ -88,36 +89,36 @@ static Expression* toABI(Expression* value, Module* module) {
 static Expression* fromABI(Expression* value, Type type, Module* module) {
   Builder builder(*module);
   switch (type) {
-    case i32: {
+    case Type::i32: {
       value = builder.makeUnary(WrapInt64, value);
       break;
     }
-    case i64: {
+    case Type::i64: {
       // already good
       break;
     }
-    case f32: {
+    case Type::f32: {
       value = builder.makeUnary(ReinterpretInt32,
                                 builder.makeUnary(WrapInt64, value));
       break;
     }
-    case f64: {
+    case Type::f64: {
       value = builder.makeUnary(ReinterpretInt64, value);
       break;
     }
-    case v128: {
+    case Type::v128: {
       WASM_UNREACHABLE("v128 not implemented yet");
     }
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref: {
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref: {
       WASM_UNREACHABLE("reference types cannot be converted from i64");
     }
-    case none: {
+    case Type::none: {
       value = builder.makeDrop(value);
     }
-    case unreachable: {
+    case Type::unreachable: {
       // can leave it, the call isn't taken anyhow
       break;
     }
@@ -143,12 +144,12 @@ struct ParallelFuncCastEmulation
     }
     // Add extra operands as needed.
     while (curr->operands.size() < NUM_PARAMS) {
-      curr->operands.push_back(LiteralUtils::makeZero(i64, *getModule()));
+      curr->operands.push_back(LiteralUtils::makeZero(Type::i64, *getModule()));
     }
     // Set the new types
     curr->sig = ABIType;
     auto oldType = curr->type;
-    curr->type = i64;
+    curr->type = Type::i64;
     curr->finalize(); // may be unreachable
     // Fix up return value
     replaceCurrent(fromABI(curr, oldType, getModule()));
@@ -203,12 +204,12 @@ private:
     std::vector<Expression*> callOperands;
     for (Index i = 0; i < params.size(); i++) {
       callOperands.push_back(
-        fromABI(builder.makeLocalGet(i, i64), params[i], module));
+        fromABI(builder.makeLocalGet(i, Type::i64), params[i], module));
     }
     auto* call = builder.makeCall(name, callOperands, type);
     std::vector<Type> thunkParams;
     for (Index i = 0; i < NUM_PARAMS; i++) {
-      thunkParams.push_back(i64);
+      thunkParams.push_back(Type::i64);
     }
     auto* thunkFunc =
       builder.makeFunction(thunk,
diff --git a/src/passes/I64ToI32Lowering.cpp b/src/passes/I64ToI32Lowering.cpp
index c9a4f46ea..c3ed6fb04 100644
--- a/src/passes/I64ToI32Lowering.cpp
+++ b/src/passes/I64ToI32Lowering.cpp
@@ -109,13 +109,13 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     // add new globals for high bits
     for (size_t i = 0, globals = module->globals.size(); i < globals; ++i) {
       auto* curr = module->globals[i].get();
-      if (curr->type != i64) {
+      if (curr->type != Type::i64) {
         continue;
       }
       originallyI64Globals.insert(curr->name);
-      curr->type = i32;
+      curr->type = Type::i32;
       auto* high = builder->makeGlobal(makeHighName(curr->name),
-                                       i32,
+                                       Type::i32,
                                        builder->makeConst(Literal(int32_t(0))),
                                        Builder::Mutable);
       module->addGlobal(high);
@@ -125,21 +125,22 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
         if (auto* c = curr->init->dynCast<Const>()) {
           uint64_t value = c->value.geti64();
           c->value = Literal(uint32_t(value));
-          c->type = i32;
+          c->type = Type::i32;
           high->init = builder->makeConst(Literal(uint32_t(value >> 32)));
         } else if (auto* get = curr->init->dynCast<GlobalGet>()) {
-          high->init = builder->makeGlobalGet(makeHighName(get->name), i32);
+          high->init =
+            builder->makeGlobalGet(makeHighName(get->name), Type::i32);
         } else {
           WASM_UNREACHABLE("unexpected expression type");
         }
-        curr->init->type = i32;
+        curr->init->type = Type::i32;
       }
     }
 
     // For functions that return 64-bit values, we use this global variable
     // to return the high 32 bits.
     auto* highBits = new Global();
-    highBits->type = i32;
+    highBits->type = Type::i32;
     highBits->name = INT64_TO_32_HIGH_BITS;
     highBits->init = builder->makeConst(Literal(int32_t(0)));
     highBits->mutable_ = true;
@@ -173,7 +174,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
         (i < oldFunc->getVarIndexBase())
           ? Builder::addParam
           : static_cast<Index (*)(Function*, Name, Type)>(Builder::addVar);
-      if (paramType == i64) {
+      if (paramType == Type::i64) {
         builderFunc(func, lowName, Type::i32);
         builderFunc(func, highName, Type::i32);
         indexMap[i] = newIdx;
@@ -199,8 +200,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
         TempVar lowBits = getTemp();
         LocalSet* setLow = builder->makeLocalSet(lowBits, func->body);
         GlobalSet* setHigh = builder->makeGlobalSet(
-          INT64_TO_32_HIGH_BITS, builder->makeLocalGet(highBits, i32));
-        LocalGet* getLow = builder->makeLocalGet(lowBits, i32);
+          INT64_TO_32_HIGH_BITS, builder->makeLocalGet(highBits, Type::i32));
+        LocalGet* getLow = builder->makeLocalGet(lowBits, Type::i32);
         func->body = builder->blockify(setLow, setHigh, getLow);
       }
     }
@@ -224,7 +225,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       args.push_back(e);
       if (hasOutParam(e)) {
         TempVar argHighBits = fetchOutParam(e);
-        args.push_back(builder->makeLocalGet(argHighBits, i32));
+        args.push_back(builder->makeLocalGet(argHighBits, Type::i32));
         fixed = true;
       }
     }
@@ -238,8 +239,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     auto* call = callBuilder(args, Type::i32);
     LocalSet* doCall = builder->makeLocalSet(lowBits, call);
     LocalSet* setHigh = builder->makeLocalSet(
-      highBits, builder->makeGlobalGet(INT64_TO_32_HIGH_BITS, i32));
-    LocalGet* getLow = builder->makeLocalGet(lowBits, i32);
+      highBits, builder->makeGlobalGet(INT64_TO_32_HIGH_BITS, Type::i32));
+    LocalGet* getLow = builder->makeLocalGet(lowBits, Type::i32);
     Block* result = builder->blockify(doCall, setHigh, getLow);
     setOutParam(result, std::move(highBits));
     replaceCurrent(result);
@@ -289,13 +290,13 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     // Need to remap the local into the new naming scheme, regardless of
     // the type of the local.
     curr->index = mappedIndex;
-    if (curr->type != i64) {
+    if (curr->type != Type::i64) {
       return;
     }
-    curr->type = i32;
+    curr->type = Type::i32;
     TempVar highBits = getTemp();
     LocalSet* setHighBits = builder->makeLocalSet(
-      highBits, builder->makeLocalGet(mappedIndex + 1, i32));
+      highBits, builder->makeLocalGet(mappedIndex + 1, Type::i32));
     Block* result = builder->blockify(setHighBits, curr);
     replaceCurrent(result);
     setOutParam(result, std::move(highBits));
@@ -304,11 +305,11 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
   void lowerTee(LocalSet* curr) {
     TempVar highBits = fetchOutParam(curr->value);
     TempVar tmp = getTemp();
-    curr->type = i32;
+    curr->type = Type::i32;
     LocalSet* setLow = builder->makeLocalSet(tmp, curr);
     LocalSet* setHigh = builder->makeLocalSet(
-      curr->index + 1, builder->makeLocalGet(highBits, i32));
-    LocalGet* getLow = builder->makeLocalGet(tmp, i32);
+      curr->index + 1, builder->makeLocalGet(highBits, Type::i32));
+    LocalGet* getLow = builder->makeLocalGet(tmp, Type::i32);
     Block* result = builder->blockify(setLow, setHigh, getLow);
     replaceCurrent(result);
     setOutParam(result, std::move(highBits));
@@ -327,8 +328,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       return;
     }
     TempVar highBits = fetchOutParam(curr->value);
-    auto* setHigh = builder->makeLocalSet(mappedIndex + 1,
-                                          builder->makeLocalGet(highBits, i32));
+    auto* setHigh = builder->makeLocalSet(
+      mappedIndex + 1, builder->makeLocalGet(highBits, Type::i32));
     Block* result = builder->blockify(curr, setHigh);
     replaceCurrent(result);
   }
@@ -340,10 +341,10 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     if (!originallyI64Globals.count(curr->name)) {
       return;
     }
-    curr->type = i32;
+    curr->type = Type::i32;
     TempVar highBits = getTemp();
     LocalSet* setHighBits = builder->makeLocalSet(
-      highBits, builder->makeGlobalGet(makeHighName(curr->name), i32));
+      highBits, builder->makeGlobalGet(makeHighName(curr->name), Type::i32));
     Block* result = builder->blockify(setHighBits, curr);
     replaceCurrent(result);
     setOutParam(result, std::move(highBits));
@@ -358,12 +359,12 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     }
     TempVar highBits = fetchOutParam(curr->value);
     auto* setHigh = builder->makeGlobalSet(
-      makeHighName(curr->name), builder->makeLocalGet(highBits, i32));
+      makeHighName(curr->name), builder->makeLocalGet(highBits, Type::i32));
     replaceCurrent(builder->makeSequence(curr, setHigh));
   }
 
   void visitLoad(Load* curr) {
-    if (curr->type != i64) {
+    if (curr->type != Type::i64) {
       return;
     }
     assert(!curr->isAtomic && "atomic load not implemented");
@@ -379,26 +380,27 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
                           curr->signed_,
                           curr->offset + 4,
                           std::min(uint32_t(curr->align), uint32_t(4)),
-                          builder->makeLocalGet(ptrTemp, i32),
-                          i32));
+                          builder->makeLocalGet(ptrTemp, Type::i32),
+                          Type::i32));
     } else if (curr->signed_) {
       loadHigh = builder->makeLocalSet(
         highBits,
         builder->makeBinary(ShrSInt32,
-                            builder->makeLocalGet(lowBits, i32),
+                            builder->makeLocalGet(lowBits, Type::i32),
                             builder->makeConst(Literal(int32_t(31)))));
     } else {
       loadHigh = builder->makeLocalSet(highBits,
                                        builder->makeConst(Literal(int32_t(0))));
     }
-    curr->type = i32;
+    curr->type = Type::i32;
     curr->bytes = std::min(curr->bytes, uint8_t(4));
     curr->align = std::min(uint32_t(curr->align), uint32_t(4));
-    curr->ptr = builder->makeLocalGet(ptrTemp, i32);
-    Block* result = builder->blockify(setPtr,
-                                      builder->makeLocalSet(lowBits, curr),
-                                      loadHigh,
-                                      builder->makeLocalGet(lowBits, i32));
+    curr->ptr = builder->makeLocalGet(ptrTemp, Type::i32);
+    Block* result =
+      builder->blockify(setPtr,
+                        builder->makeLocalSet(lowBits, curr),
+                        loadHigh,
+                        builder->makeLocalGet(lowBits, Type::i32));
     replaceCurrent(result);
     setOutParam(result, std::move(highBits));
   }
@@ -413,19 +415,19 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     uint8_t bytes = curr->bytes;
     curr->bytes = std::min(curr->bytes, uint8_t(4));
     curr->align = std::min(uint32_t(curr->align), uint32_t(4));
-    curr->valueType = i32;
+    curr->valueType = Type::i32;
     if (bytes == 8) {
       TempVar ptrTemp = getTemp();
       LocalSet* setPtr = builder->makeLocalSet(ptrTemp, curr->ptr);
-      curr->ptr = builder->makeLocalGet(ptrTemp, i32);
+      curr->ptr = builder->makeLocalGet(ptrTemp, Type::i32);
       curr->finalize();
       Store* storeHigh =
         builder->makeStore(4,
                            curr->offset + 4,
                            std::min(uint32_t(curr->align), uint32_t(4)),
-                           builder->makeLocalGet(ptrTemp, i32),
-                           builder->makeLocalGet(highBits, i32),
-                           i32);
+                           builder->makeLocalGet(ptrTemp, Type::i32),
+                           builder->makeLocalGet(highBits, Type::i32),
+                           Type::i32);
       replaceCurrent(builder->blockify(setPtr, curr, storeHigh));
     }
   }
@@ -442,7 +444,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     if (!getFunction()) {
       return; // if in a global init, skip - we already handled that.
     }
-    if (curr->type != i64) {
+    if (curr->type != Type::i64) {
       return;
     }
     TempVar highBits = getTemp();
@@ -463,7 +465,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     auto* result = builder->makeUnary(
       EqZInt32,
       builder->makeBinary(
-        OrInt32, curr->value, builder->makeLocalGet(highBits, i32)));
+        OrInt32, curr->value, builder->makeLocalGet(highBits, Type::i32)));
 
     replaceCurrent(result);
   }
@@ -485,11 +487,11 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     LocalSet* setHigh = builder->makeLocalSet(
       highBits,
       builder->makeBinary(ShrSInt32,
-                          builder->makeLocalGet(lowBits, i32),
+                          builder->makeLocalGet(lowBits, Type::i32),
                           builder->makeConst(Literal(int32_t(31)))));
 
-    Block* result =
-      builder->blockify(setLow, setHigh, builder->makeLocalGet(lowBits, i32));
+    Block* result = builder->blockify(
+      setLow, setHigh, builder->makeLocalGet(lowBits, Type::i32));
 
     setOutParam(result, std::move(highBits));
     replaceCurrent(result);
@@ -506,15 +508,16 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     // our f64 through memory at address 0
     TempVar highBits = getTemp();
     Block* result = builder->blockify(
-      builder->makeCall(ABI::wasm2js::SCRATCH_STORE_F64, {curr->value}, none),
+      builder->makeCall(
+        ABI::wasm2js::SCRATCH_STORE_F64, {curr->value}, Type::none),
       builder->makeLocalSet(
         highBits,
         builder->makeCall(ABI::wasm2js::SCRATCH_LOAD_I32,
                           {builder->makeConst(Literal(int32_t(1)))},
-                          i32)),
+                          Type::i32)),
       builder->makeCall(ABI::wasm2js::SCRATCH_LOAD_I32,
                         {builder->makeConst(Literal(int32_t(0)))},
-                        i32));
+                        Type::i32));
     setOutParam(result, std::move(highBits));
     replaceCurrent(result);
     MemoryUtils::ensureExists(getModule()->memory);
@@ -528,12 +531,12 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     Block* result = builder->blockify(
       builder->makeCall(ABI::wasm2js::SCRATCH_STORE_I32,
                         {builder->makeConst(Literal(int32_t(0))), curr->value},
-                        none),
+                        Type::none),
       builder->makeCall(ABI::wasm2js::SCRATCH_STORE_I32,
                         {builder->makeConst(Literal(int32_t(1))),
-                         builder->makeLocalGet(highBits, i32)},
-                        none),
-      builder->makeCall(ABI::wasm2js::SCRATCH_LOAD_F64, {}, f64));
+                         builder->makeLocalGet(highBits, Type::i32)},
+                        Type::none),
+      builder->makeCall(ABI::wasm2js::SCRATCH_LOAD_F64, {}, Type::f64));
     replaceCurrent(result);
     MemoryUtils::ensureExists(getModule()->memory);
     ABI::wasm2js::ensureScratchMemoryHelpers(getModule());
@@ -567,7 +570,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
         u32Max = Literal(((float)UINT_MAX) + 1);
         trunc = TruncUFloat32ToInt32;
         convert = ConvertUInt32ToFloat32;
-        localType = f32;
+        localType = Type::f32;
         abs = AbsFloat32;
         ge = GeFloat32;
         gt = GtFloat32;
@@ -585,7 +588,7 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
         u32Max = Literal(((double)UINT_MAX) + 1);
         trunc = TruncUFloat64ToInt32;
         convert = ConvertUInt32ToFloat64;
-        localType = f64;
+        localType = Type::f64;
         abs = AbsFloat64;
         ge = GeFloat64;
         gt = GtFloat64;
@@ -682,12 +685,12 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeBinary(
         AddFloat64,
         builder->makeUnary(ConvertUInt32ToFloat64,
-                           builder->makeLocalGet(lowBits, i32)),
+                           builder->makeLocalGet(lowBits, Type::i32)),
         builder->makeBinary(
           MulFloat64,
           builder->makeConst(Literal((double)UINT_MAX + 1)),
           builder->makeUnary(convertHigh,
-                             builder->makeLocalGet(highBits, i32)))));
+                             builder->makeLocalGet(highBits, Type::i32)))));
 
     switch (curr->op) {
       case ConvertSInt64ToFloat32:
@@ -711,20 +714,20 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       TempVar firstResult = getTemp();
       LocalSet* setFirst = builder->makeLocalSet(
         firstResult,
-        builder->makeUnary(op32, builder->makeLocalGet(first, i32)));
+        builder->makeUnary(op32, builder->makeLocalGet(first, Type::i32)));
 
       Binary* check =
         builder->makeBinary(EqInt32,
-                            builder->makeLocalGet(firstResult, i32),
+                            builder->makeLocalGet(firstResult, Type::i32),
                             builder->makeConst(Literal(int32_t(32))));
 
       If* conditional = builder->makeIf(
         check,
         builder->makeBinary(
           AddInt32,
-          builder->makeUnary(op32, builder->makeLocalGet(second, i32)),
+          builder->makeUnary(op32, builder->makeLocalGet(second, Type::i32)),
           builder->makeConst(Literal(int32_t(32)))),
-        builder->makeLocalGet(firstResult, i32));
+        builder->makeLocalGet(firstResult, Type::i32));
 
       LocalSet* setHigh = builder->makeLocalSet(
         highResult, builder->makeConst(Literal(int32_t(0))));
@@ -783,7 +786,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     if (handleUnreachable(curr)) {
       return;
     }
-    assert(hasOutParam(curr->value) || curr->type == i64 || curr->type == f64);
+    assert(hasOutParam(curr->value) || curr->type == Type::i64 ||
+           curr->type == Type::f64);
     switch (curr->op) {
       case ClzInt64:
       case CtzInt64:
@@ -837,24 +841,24 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     LocalSet* addLow = builder->makeLocalSet(
       lowResult,
       builder->makeBinary(AddInt32,
-                          builder->makeLocalGet(leftLow, i32),
-                          builder->makeLocalGet(rightLow, i32)));
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32)));
     LocalSet* addHigh = builder->makeLocalSet(
       highResult,
       builder->makeBinary(AddInt32,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(rightHigh, i32)));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32)));
     LocalSet* carryBit = builder->makeLocalSet(
       highResult,
       builder->makeBinary(AddInt32,
-                          builder->makeLocalGet(highResult, i32),
+                          builder->makeLocalGet(highResult, Type::i32),
                           builder->makeConst(Literal(int32_t(1)))));
-    If* checkOverflow =
-      builder->makeIf(builder->makeBinary(LtUInt32,
-                                          builder->makeLocalGet(lowResult, i32),
-                                          builder->makeLocalGet(rightLow, i32)),
-                      carryBit);
-    LocalGet* getLow = builder->makeLocalGet(lowResult, i32);
+    If* checkOverflow = builder->makeIf(
+      builder->makeBinary(LtUInt32,
+                          builder->makeLocalGet(lowResult, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32)),
+      carryBit);
+    LocalGet* getLow = builder->makeLocalGet(lowResult, Type::i32);
     result = builder->blockify(result, addLow, addHigh, checkOverflow, getLow);
     setOutParam(result, std::move(highResult));
     return result;
@@ -871,24 +875,24 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     LocalSet* subLow = builder->makeLocalSet(
       lowResult,
       builder->makeBinary(SubInt32,
-                          builder->makeLocalGet(leftLow, i32),
-                          builder->makeLocalGet(rightLow, i32)));
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32)));
     LocalSet* borrowBit = builder->makeLocalSet(
       borrow,
       builder->makeBinary(LtUInt32,
-                          builder->makeLocalGet(leftLow, i32),
-                          builder->makeLocalGet(rightLow, i32)));
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32)));
     LocalSet* subHigh1 = builder->makeLocalSet(
       highResult,
       builder->makeBinary(AddInt32,
-                          builder->makeLocalGet(borrow, i32),
-                          builder->makeLocalGet(rightHigh, i32)));
+                          builder->makeLocalGet(borrow, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32)));
     LocalSet* subHigh2 = builder->makeLocalSet(
       highResult,
       builder->makeBinary(SubInt32,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(highResult, i32)));
-    LocalGet* getLow = builder->makeLocalGet(lowResult, i32);
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(highResult, Type::i32)));
+    LocalGet* getLow = builder->makeLocalGet(lowResult, Type::i32);
     result =
       builder->blockify(result, subLow, borrowBit, subHigh1, subHigh2, getLow);
     setOutParam(result, std::move(highResult));
@@ -920,11 +924,11 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeLocalSet(
         rightHigh,
         builder->makeBinary(op32,
-                            builder->makeLocalGet(leftHigh, i32),
-                            builder->makeLocalGet(rightHigh, i32))),
+                            builder->makeLocalGet(leftHigh, Type::i32),
+                            builder->makeLocalGet(rightHigh, Type::i32))),
       builder->makeBinary(op32,
-                          builder->makeLocalGet(leftLow, i32),
-                          builder->makeLocalGet(rightLow, i32)));
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32)));
     setOutParam(result, std::move(rightHigh));
     return result;
   }
@@ -934,8 +938,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeLocalSet(
         highBits,
         builder->makeBinary(ShlInt32,
-                            builder->makeLocalGet(leftLow, i32),
-                            builder->makeLocalGet(shift, i32))),
+                            builder->makeLocalGet(leftLow, Type::i32),
+                            builder->makeLocalGet(shift, Type::i32))),
       builder->makeConst(Literal(int32_t(0))));
   }
 
@@ -950,19 +954,19 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeLocalSet(
         highBits,
         builder->makeBinary(ShrSInt32,
-                            builder->makeLocalGet(leftHigh, i32),
+                            builder->makeLocalGet(leftHigh, Type::i32),
                             builder->makeConst(Literal(int32_t(31))))),
       builder->makeBinary(ShrSInt32,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(shift, i32)));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32)));
   }
 
   Block* makeLargeShrU(Index highBits, Index leftHigh, Index shift) {
     return builder->blockify(
       builder->makeLocalSet(highBits, builder->makeConst(Literal(int32_t(0)))),
       builder->makeBinary(ShrUInt32,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(shift, i32)));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32)));
   }
 
   Block* makeSmallShl(Index highBits,
@@ -975,17 +979,17 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       AndInt32,
       shiftMask,
       builder->makeBinary(
-        ShrUInt32, builder->makeLocalGet(leftLow, i32), widthLessShift));
+        ShrUInt32, builder->makeLocalGet(leftLow, Type::i32), widthLessShift));
     Binary* shiftHigh =
       builder->makeBinary(ShlInt32,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(shift, i32));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32));
     return builder->blockify(
       builder->makeLocalSet(
         highBits, builder->makeBinary(OrInt32, shiftedInBits, shiftHigh)),
       builder->makeBinary(ShlInt32,
-                          builder->makeLocalGet(leftLow, i32),
-                          builder->makeLocalGet(shift, i32)));
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32)));
   }
 
   // a >> b where `b` < 32
@@ -1003,17 +1007,18 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     Binary* shiftedInBits = builder->makeBinary(
       ShlInt32,
       builder->makeBinary(
-        AndInt32, shiftMask, builder->makeLocalGet(leftHigh, i32)),
+        AndInt32, shiftMask, builder->makeLocalGet(leftHigh, Type::i32)),
       widthLessShift);
-    Binary* shiftLow = builder->makeBinary(ShrUInt32,
-                                           builder->makeLocalGet(leftLow, i32),
-                                           builder->makeLocalGet(shift, i32));
+    Binary* shiftLow =
+      builder->makeBinary(ShrUInt32,
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32));
     return builder->blockify(
       builder->makeLocalSet(
         highBits,
         builder->makeBinary(ShrSInt32,
-                            builder->makeLocalGet(leftHigh, i32),
-                            builder->makeLocalGet(shift, i32))),
+                            builder->makeLocalGet(leftHigh, Type::i32),
+                            builder->makeLocalGet(shift, Type::i32))),
       builder->makeBinary(OrInt32, shiftedInBits, shiftLow));
   }
 
@@ -1026,17 +1031,18 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     Binary* shiftedInBits = builder->makeBinary(
       ShlInt32,
       builder->makeBinary(
-        AndInt32, shiftMask, builder->makeLocalGet(leftHigh, i32)),
+        AndInt32, shiftMask, builder->makeLocalGet(leftHigh, Type::i32)),
       widthLessShift);
-    Binary* shiftLow = builder->makeBinary(ShrUInt32,
-                                           builder->makeLocalGet(leftLow, i32),
-                                           builder->makeLocalGet(shift, i32));
+    Binary* shiftLow =
+      builder->makeBinary(ShrUInt32,
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(shift, Type::i32));
     return builder->blockify(
       builder->makeLocalSet(
         highBits,
         builder->makeBinary(ShrUInt32,
-                            builder->makeLocalGet(leftHigh, i32),
-                            builder->makeLocalGet(shift, i32))),
+                            builder->makeLocalGet(leftHigh, Type::i32),
+                            builder->makeLocalGet(shift, Type::i32))),
       builder->makeBinary(OrInt32, shiftedInBits, shiftLow));
   }
 
@@ -1058,13 +1064,13 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     LocalSet* setShift = builder->makeLocalSet(
       shift,
       builder->makeBinary(AndInt32,
-                          builder->makeLocalGet(rightLow, i32),
+                          builder->makeLocalGet(rightLow, Type::i32),
                           builder->makeConst(Literal(int32_t(32 - 1)))));
     Binary* isLargeShift = builder->makeBinary(
       LeUInt32,
       builder->makeConst(Literal(int32_t(32))),
       builder->makeBinary(AndInt32,
-                          builder->makeLocalGet(rightLow, i32),
+                          builder->makeLocalGet(rightLow, Type::i32),
                           builder->makeConst(Literal(int32_t(64 - 1)))));
     Block* largeShiftBlock;
     switch (op) {
@@ -1084,12 +1090,12 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       SubInt32,
       builder->makeBinary(ShlInt32,
                           builder->makeConst(Literal(int32_t(1))),
-                          builder->makeLocalGet(shift, i32)),
+                          builder->makeLocalGet(shift, Type::i32)),
       builder->makeConst(Literal(int32_t(1))));
     Binary* widthLessShift =
       builder->makeBinary(SubInt32,
                           builder->makeConst(Literal(int32_t(32))),
-                          builder->makeLocalGet(shift, i32));
+                          builder->makeLocalGet(shift, Type::i32));
     Block* smallShiftBlock;
     switch (op) {
       case ShlInt64: {
@@ -1127,11 +1133,11 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeBinary(
         AndInt32,
         builder->makeBinary(EqInt32,
-                            builder->makeLocalGet(leftLow, i32),
-                            builder->makeLocalGet(rightLow, i32)),
+                            builder->makeLocalGet(leftLow, Type::i32),
+                            builder->makeLocalGet(rightLow, Type::i32)),
         builder->makeBinary(EqInt32,
-                            builder->makeLocalGet(leftHigh, i32),
-                            builder->makeLocalGet(rightHigh, i32))));
+                            builder->makeLocalGet(leftHigh, Type::i32),
+                            builder->makeLocalGet(rightHigh, Type::i32))));
   }
 
   Block* lowerNe(Block* result,
@@ -1144,11 +1150,11 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeBinary(
         OrInt32,
         builder->makeBinary(NeInt32,
-                            builder->makeLocalGet(leftLow, i32),
-                            builder->makeLocalGet(rightLow, i32)),
+                            builder->makeLocalGet(leftLow, Type::i32),
+                            builder->makeLocalGet(rightLow, Type::i32)),
         builder->makeBinary(NeInt32,
-                            builder->makeLocalGet(leftHigh, i32),
-                            builder->makeLocalGet(rightHigh, i32))));
+                            builder->makeLocalGet(leftHigh, Type::i32),
+                            builder->makeLocalGet(rightHigh, Type::i32))));
   }
 
   Block* lowerUComp(BinaryOp op,
@@ -1180,14 +1186,16 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     }
     Binary* compHigh =
       builder->makeBinary(highOp,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(rightHigh, i32));
-    Binary* eqHigh = builder->makeBinary(EqInt32,
-                                         builder->makeLocalGet(leftHigh, i32),
-                                         builder->makeLocalGet(rightHigh, i32));
-    Binary* compLow = builder->makeBinary(lowOp,
-                                          builder->makeLocalGet(leftLow, i32),
-                                          builder->makeLocalGet(rightLow, i32));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32));
+    Binary* eqHigh =
+      builder->makeBinary(EqInt32,
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32));
+    Binary* compLow =
+      builder->makeBinary(lowOp,
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32));
     return builder->blockify(
       result,
       builder->makeBinary(
@@ -1227,15 +1235,16 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     }
     Binary* compHigh1 =
       builder->makeBinary(highOp1,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(rightHigh, i32));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32));
     Binary* compHigh2 =
       builder->makeBinary(highOp2,
-                          builder->makeLocalGet(leftHigh, i32),
-                          builder->makeLocalGet(rightHigh, i32));
-    Binary* compLow = builder->makeBinary(lowOp,
-                                          builder->makeLocalGet(leftLow, i32),
-                                          builder->makeLocalGet(rightLow, i32));
+                          builder->makeLocalGet(leftHigh, Type::i32),
+                          builder->makeLocalGet(rightHigh, Type::i32));
+    Binary* compLow =
+      builder->makeBinary(lowOp,
+                          builder->makeLocalGet(leftLow, Type::i32),
+                          builder->makeLocalGet(rightLow, Type::i32));
     If* lowIf = builder->makeIf(compLow,
                                 builder->makeConst(Literal(int32_t(0))),
                                 builder->makeConst(Literal(int32_t(1))));
@@ -1405,14 +1414,14 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
       builder->makeLocalSet(
         lowBits,
         builder->makeSelect(
-          builder->makeLocalGet(cond, i32), curr->ifTrue, curr->ifFalse)),
+          builder->makeLocalGet(cond, Type::i32), curr->ifTrue, curr->ifFalse)),
       builder->makeLocalSet(
         highBits,
         builder->makeSelect(
-          builder->makeLocalGet(cond, i32),
-          builder->makeLocalGet(fetchOutParam(curr->ifTrue), i32),
-          builder->makeLocalGet(fetchOutParam(curr->ifFalse), i32))),
-      builder->makeLocalGet(lowBits, i32));
+          builder->makeLocalGet(cond, Type::i32),
+          builder->makeLocalGet(fetchOutParam(curr->ifTrue), Type::i32),
+          builder->makeLocalGet(fetchOutParam(curr->ifFalse), Type::i32))),
+      builder->makeLocalGet(lowBits, Type::i32));
     setOutParam(result, std::move(highBits));
     replaceCurrent(result);
   }
@@ -1433,8 +1442,8 @@ struct I64ToI32Lowering : public WalkerPass<PostWalker<I64ToI32Lowering>> {
     TempVar highBits = fetchOutParam(curr->value);
     LocalSet* setLow = builder->makeLocalSet(lowBits, curr->value);
     GlobalSet* setHigh = builder->makeGlobalSet(
-      INT64_TO_32_HIGH_BITS, builder->makeLocalGet(highBits, i32));
-    curr->value = builder->makeLocalGet(lowBits, i32);
+      INT64_TO_32_HIGH_BITS, builder->makeLocalGet(highBits, Type::i32));
+    curr->value = builder->makeLocalGet(lowBits, Type::i32);
     Block* result = builder->blockify(setLow, setHigh, curr);
     replaceCurrent(result);
   }
@@ -1448,7 +1457,7 @@ private:
   std::unordered_set<Name> originallyI64Globals;
   Index nextTemp;
 
-  TempVar getTemp(Type ty = i32) {
+  TempVar getTemp(Type ty = Type::i32) {
     Index ret;
     auto& freeList = freeTemps[(int)ty];
     if (freeList.size() > 0) {
@@ -1486,7 +1495,7 @@ private:
   // unconditionally before themselves, so it is not valid for an if,
   // in particular.
   bool handleUnreachable(Expression* curr) {
-    if (curr->type != unreachable) {
+    if (curr->type != Type::unreachable) {
       return false;
     }
     std::vector<Expression*> children;
@@ -1494,7 +1503,7 @@ private:
     for (auto* child : ChildIterator(curr)) {
       if (child->type.isConcrete()) {
         child = builder->makeDrop(child);
-      } else if (child->type == unreachable) {
+      } else if (child->type == Type::unreachable) {
         hasUnreachable = true;
       }
       children.push_back(child);
@@ -1505,7 +1514,7 @@ private:
     // This has an unreachable child, so we can replace it with
     // the children.
     auto* block = builder->makeBlock(children);
-    assert(block->type == unreachable);
+    assert(block->type == Type::unreachable);
     replaceCurrent(block);
     return true;
   }
diff --git a/src/passes/Inlining.cpp b/src/passes/Inlining.cpp
index c43d41e7f..5737359a3 100644
--- a/src/passes/Inlining.cpp
+++ b/src/passes/Inlining.cpp
@@ -154,12 +154,12 @@ struct Planner : public WalkerPass<PostWalker<Planner>> {
     bool isUnreachable;
     if (curr->isReturn) {
       // Tail calls are only actually unreachable if an argument is
-      isUnreachable =
-        std::any_of(curr->operands.begin(),
-                    curr->operands.end(),
-                    [](Expression* op) { return op->type == unreachable; });
+      isUnreachable = std::any_of(
+        curr->operands.begin(), curr->operands.end(), [](Expression* op) {
+          return op->type == Type::unreachable;
+        });
     } else {
-      isUnreachable = curr->type == unreachable;
+      isUnreachable = curr->type == Type::unreachable;
     }
     if (state->worthInlining.count(curr->target) && !isUnreachable &&
         curr->target != getFunction()->name) {
@@ -273,7 +273,7 @@ doInlining(Module* module, Function* into, const InliningAction& action) {
   // contained void, that is fine too. a bad case is a void function in which
   // we have unreachable code, so we would be replacing a void call with an
   // unreachable.
-  if (contents->type == unreachable && block->type == none) {
+  if (contents->type == Type::unreachable && block->type == Type::none) {
     // Make the block reachable by adding a break to it
     block->list.push_back(builder.makeBreak(block->name));
   }
diff --git a/src/passes/InstrumentLocals.cpp b/src/passes/InstrumentLocals.cpp
index ae35ec2d1..3e3be6244 100644
--- a/src/passes/InstrumentLocals.cpp
+++ b/src/passes/InstrumentLocals.cpp
@@ -75,33 +75,33 @@ struct InstrumentLocals : public WalkerPass<PostWalker<InstrumentLocals>> {
     Builder builder(*getModule());
     Name import;
     switch (curr->type) {
-      case i32:
+      case Type::i32:
         import = get_i32;
         break;
-      case i64:
+      case Type::i64:
         return; // TODO
-      case f32:
+      case Type::f32:
         import = get_f32;
         break;
-      case f64:
+      case Type::f64:
         import = get_f64;
         break;
-      case v128:
+      case Type::v128:
         assert(false && "v128 not implemented yet");
-      case funcref:
+      case Type::funcref:
         import = get_funcref;
         break;
-      case anyref:
+      case Type::anyref:
         import = get_anyref;
         break;
-      case nullref:
+      case Type::nullref:
         import = get_nullref;
         break;
-      case exnref:
+      case Type::exnref:
         import = get_exnref;
         break;
-      case none:
-      case unreachable:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
     replaceCurrent(
@@ -123,34 +123,34 @@ struct InstrumentLocals : public WalkerPass<PostWalker<InstrumentLocals>> {
     Builder builder(*getModule());
     Name import;
     switch (curr->value->type) {
-      case i32:
+      case Type::i32:
         import = set_i32;
         break;
-      case i64:
+      case Type::i64:
         return; // TODO
-      case f32:
+      case Type::f32:
         import = set_f32;
         break;
-      case f64:
+      case Type::f64:
         import = set_f64;
         break;
-      case v128:
+      case Type::v128:
         assert(false && "v128 not implemented yet");
-      case funcref:
+      case Type::funcref:
         import = set_funcref;
         break;
-      case anyref:
+      case Type::anyref:
         import = set_anyref;
         break;
-      case nullref:
+      case Type::nullref:
         import = set_nullref;
         break;
-      case exnref:
+      case Type::exnref:
         import = set_exnref;
         break;
-      case unreachable:
+      case Type::unreachable:
         return; // nothing to do here
-      case none:
+      case Type::none:
         WASM_UNREACHABLE("unexpected type");
     }
     curr->value =
diff --git a/src/passes/InstrumentMemory.cpp b/src/passes/InstrumentMemory.cpp
index 9a805b19b..54f763734 100644
--- a/src/passes/InstrumentMemory.cpp
+++ b/src/passes/InstrumentMemory.cpp
@@ -84,19 +84,19 @@ struct InstrumentMemory : public WalkerPass<PostWalker<InstrumentMemory>> {
                         builder.makeConst(Literal(int32_t(curr->bytes))),
                         builder.makeConst(Literal(int32_t(curr->offset.addr))),
                         curr->ptr},
-                       i32);
+                       Type::i32);
     Name target;
     switch (curr->type) {
-      case i32:
+      case Type::i32:
         target = load_val_i32;
         break;
-      case i64:
+      case Type::i64:
         target = load_val_i64;
         break;
-      case f32:
+      case Type::f32:
         target = load_val_f32;
         break;
-      case f64:
+      case Type::f64:
         target = load_val_f64;
         break;
       default:
@@ -115,19 +115,19 @@ struct InstrumentMemory : public WalkerPass<PostWalker<InstrumentMemory>> {
                         builder.makeConst(Literal(int32_t(curr->bytes))),
                         builder.makeConst(Literal(int32_t(curr->offset.addr))),
                         curr->ptr},
-                       i32);
+                       Type::i32);
     Name target;
     switch (curr->value->type) {
-      case i32:
+      case Type::i32:
         target = store_val_i32;
         break;
-      case i64:
+      case Type::i64:
         target = store_val_i64;
         break;
-      case f32:
+      case Type::f32:
         target = store_val_f32;
         break;
-      case f64:
+      case Type::f64:
         target = store_val_f64;
         break;
       default:
diff --git a/src/passes/LegalizeJSInterface.cpp b/src/passes/LegalizeJSInterface.cpp
index df6651b0d..3a28e1745 100644
--- a/src/passes/LegalizeJSInterface.cpp
+++ b/src/passes/LegalizeJSInterface.cpp
@@ -244,7 +244,7 @@ private:
       auto* block = builder.makeBlock();
       block->list.push_back(builder.makeLocalSet(index, call));
       block->list.push_back(builder.makeCall(
-        f->name, {I64Utilities::getI64High(builder, index)}, none));
+        f->name, {I64Utilities::getI64High(builder, index)}, Type::none));
       block->list.push_back(I64Utilities::getI64Low(builder, index));
       block->finalize();
       legal->body = block;
@@ -281,8 +281,8 @@ private:
       if (imParams[i] == Type::i64) {
         call->operands.push_back(I64Utilities::getI64Low(builder, i));
         call->operands.push_back(I64Utilities::getI64High(builder, i));
-        params.push_back(i32);
-        params.push_back(i32);
+        params.push_back(Type::i32);
+        params.push_back(Type::i32);
       } else {
         call->operands.push_back(builder.makeLocalGet(i, imParams[i]));
         params.push_back(imParams[i]);
diff --git a/src/passes/LogExecution.cpp b/src/passes/LogExecution.cpp
index 611f79dfd..a6caf1c1f 100644
--- a/src/passes/LogExecution.cpp
+++ b/src/passes/LogExecution.cpp
@@ -72,7 +72,7 @@ private:
     Builder builder(*getModule());
     return builder.makeSequence(
       builder.makeCall(
-        LOGGER, {builder.makeConst(Literal(int32_t(id++)))}, none),
+        LOGGER, {builder.makeConst(Literal(int32_t(id++)))}, Type::none),
       curr);
   }
 };
diff --git a/src/passes/LoopInvariantCodeMotion.cpp b/src/passes/LoopInvariantCodeMotion.cpp
index c4880114d..a95f4c8eb 100644
--- a/src/passes/LoopInvariantCodeMotion.cpp
+++ b/src/passes/LoopInvariantCodeMotion.cpp
@@ -189,7 +189,7 @@ struct LoopInvariantCodeMotion
   bool interestingToMove(Expression* curr) {
     // In theory we could consider blocks, but then heavy nesting of
     // switch patterns would be heavy, and almost always pointless.
-    if (curr->type != none || curr->is<Nop>() || curr->is<Block>() ||
+    if (curr->type != Type::none || curr->is<Nop>() || curr->is<Block>() ||
         curr->is<Loop>()) {
       return false;
     }
diff --git a/src/passes/MergeBlocks.cpp b/src/passes/MergeBlocks.cpp
index 8e04ed47f..276c50d9e 100644
--- a/src/passes/MergeBlocks.cpp
+++ b/src/passes/MergeBlocks.cpp
@@ -148,7 +148,7 @@ struct BreakValueDropper : public ControlFlowWalker<BreakValueDropper> {
     if (curr->value && curr->name == origin) {
       Builder builder(*getModule());
       auto* value = curr->value;
-      if (value->type == unreachable) {
+      if (value->type == Type::unreachable) {
         // the break isn't even reached
         replaceCurrent(value);
         return;
@@ -172,7 +172,7 @@ struct BreakValueDropper : public ControlFlowWalker<BreakValueDropper> {
 
 static bool hasUnreachableChild(Block* block) {
   for (auto* test : block->list) {
-    if (test->type == unreachable) {
+    if (test->type == Type::unreachable) {
       return true;
     }
   }
@@ -184,7 +184,7 @@ static bool hasDeadCode(Block* block) {
   auto& list = block->list;
   auto size = list.size();
   for (size_t i = 1; i < size; i++) {
-    if (list[i - 1]->type == unreachable) {
+    if (list[i - 1]->type == Type::unreachable) {
       return true;
     }
   }
@@ -437,13 +437,13 @@ struct MergeBlocks : public WalkerPass<PostWalker<MergeBlocks>> {
       if (!block->name.is() && block->list.size() >= 2) {
         // if we move around unreachable code, type changes could occur. avoid
         // that, as anyhow it means we should have run dce before getting here
-        if (curr->type == none && hasUnreachableChild(block)) {
+        if (curr->type == Type::none && hasUnreachableChild(block)) {
           // moving the block to the outside would replace a none with an
           // unreachable
           return outer;
         }
         auto* back = block->list.back();
-        if (back->type == unreachable) {
+        if (back->type == Type::unreachable) {
           // curr is not reachable, dce could remove it; don't try anything
           // fancy here
           return outer;
diff --git a/src/passes/OptimizeAddedConstants.cpp b/src/passes/OptimizeAddedConstants.cpp
index a34d1b96d..f0c1ec2d9 100644
--- a/src/passes/OptimizeAddedConstants.cpp
+++ b/src/passes/OptimizeAddedConstants.cpp
@@ -213,7 +213,7 @@ private:
           index = parent->getHelperIndex(set);
         }
         curr->offset = result.total;
-        curr->ptr = Builder(*module).makeLocalGet(index, i32);
+        curr->ptr = Builder(*module).makeLocalGet(index, Type::i32);
         return true;
       }
     }
@@ -304,7 +304,7 @@ struct OptimizeAddedConstants
       return iter->second;
     }
     return helperIndexes[set] =
-             Builder(*getModule()).addVar(getFunction(), i32);
+             Builder(*getModule()).addVar(getFunction(), Type::i32);
   }
 
   bool isPropagatable(LocalSet* set) { return propagatable.count(set); }
@@ -387,7 +387,7 @@ private:
           }
           auto* value = *target;
           Builder builder(*module);
-          *target = builder.makeLocalGet(index, i32);
+          *target = builder.makeLocalGet(index, Type::i32);
           replaceCurrent(
             builder.makeSequence(builder.makeLocalSet(index, value), curr));
         }
diff --git a/src/passes/OptimizeInstructions.cpp b/src/passes/OptimizeInstructions.cpp
index edd6ba2b6..2372df462 100644
--- a/src/passes/OptimizeInstructions.cpp
+++ b/src/passes/OptimizeInstructions.cpp
@@ -54,9 +54,9 @@ template<typename LocalInfoProvider>
 Index getMaxBits(Expression* curr, LocalInfoProvider* localInfoProvider) {
   if (auto* const_ = curr->dynCast<Const>()) {
     switch (curr->type) {
-      case i32:
+      case Type::i32:
         return 32 - const_->value.countLeadingZeroes().geti32();
-      case i64:
+      case Type::i64:
         return 64 - const_->value.countLeadingZeroes().geti64();
       default:
         WASM_UNREACHABLE("invalid type");
@@ -179,11 +179,11 @@ Index getMaxBits(Expression* curr, LocalInfoProvider* localInfoProvider) {
     }
   }
   switch (curr->type) {
-    case i32:
+    case Type::i32:
       return 32;
-    case i64:
+    case Type::i64:
       return 64;
-    case unreachable:
+    case Type::unreachable:
       return 64; // not interesting, but don't crash
     default:
       WASM_UNREACHABLE("invalid type");
@@ -232,7 +232,7 @@ struct LocalScanner : PostWalker<LocalScanner> {
       return;
     }
     auto type = getFunction()->getLocalType(curr->index);
-    if (type != i32 && type != i64) {
+    if (type != Type::i32 && type != Type::i64) {
       return;
     }
     // an integer var, worth processing
@@ -261,9 +261,9 @@ struct LocalScanner : PostWalker<LocalScanner> {
 
   Index getBitsForType(Type type) {
     switch (type) {
-      case i32:
+      case Type::i32:
         return 32;
-      case i64:
+      case Type::i64:
         return 64;
       default:
         return -1;
@@ -334,7 +334,7 @@ struct OptimizeInstructions
     // might change (if might not be unreachable if just one arm is, for
     // example). this optimization pass focuses on actually executing code. the
     // only exceptions are control flow changes
-    if (curr->type == unreachable && !curr->is<Break>() &&
+    if (curr->type == Type::unreachable && !curr->is<Break>() &&
         !curr->is<Switch>() && !curr->is<If>()) {
       return nullptr;
     }
@@ -567,7 +567,7 @@ struct OptimizeInstructions
           }
         }
         // math operations on a constant power of 2 right side can be optimized
-        if (right->type == i32) {
+        if (right->type == Type::i32) {
           uint32_t c = right->value.geti32();
           if (IsPowerOf2(c)) {
             if (binary->op == MulInt32) {
@@ -744,7 +744,7 @@ struct OptimizeInstructions
             std::swap(iff->ifTrue, iff->ifFalse);
           }
         }
-        if (iff->condition->type != unreachable &&
+        if (iff->condition->type != Type::unreachable &&
             ExpressionAnalyzer::equal(iff->ifTrue, iff->ifFalse)) {
           // sides are identical, fold
           // if we can replace the if with one arm, and no side effects in the
@@ -763,7 +763,7 @@ struct OptimizeInstructions
               // the types diff. as the condition is reachable, that means the
               // if must be concrete while the arm is not
               assert(iff->type.isConcrete() &&
-                     iff->ifTrue->type == unreachable);
+                     iff->ifTrue->type == Type::unreachable);
               // emit a block with a forced type
               auto* ret = builder.makeBlock();
               if (needCondition) {
@@ -847,7 +847,7 @@ struct OptimizeInstructions
       if (auto* binary = store->value->dynCast<Binary>()) {
         if (binary->op == AndInt32) {
           if (auto* right = binary->right->dynCast<Const>()) {
-            if (right->type == i32) {
+            if (right->type == Type::i32) {
               auto mask = right->value.geti32();
               if ((store->bytes == 1 && mask == 0xff) ||
                   (store->bytes == 2 && mask == 0xffff)) {
@@ -866,7 +866,7 @@ struct OptimizeInstructions
       } else if (auto* unary = store->value->dynCast<Unary>()) {
         if (unary->op == WrapInt64) {
           // instead of wrapping to 32, just store some of the bits in the i64
-          store->valueType = i64;
+          store->valueType = Type::i64;
           store->value = unary->value;
         }
       }
@@ -968,11 +968,11 @@ private:
         return makeZeroExt(ext, Properties::getSignExtBits(binary));
       }
     } else if (auto* block = boolean->dynCast<Block>()) {
-      if (block->type == i32 && block->list.size() > 0) {
+      if (block->type == Type::i32 && block->list.size() > 0) {
         block->list.back() = optimizeBoolean(block->list.back());
       }
     } else if (auto* iff = boolean->dynCast<If>()) {
-      if (iff->type == i32) {
+      if (iff->type == Type::i32) {
         iff->ifTrue = optimizeBoolean(iff->ifTrue);
         iff->ifFalse = optimizeBoolean(iff->ifFalse);
       }
@@ -1469,7 +1469,7 @@ private:
       case LtUInt32:
       case GtSInt32:
       case GtUInt32:
-        return LiteralUtils::makeZero(i32, *getModule());
+        return LiteralUtils::makeZero(Type::i32, *getModule());
       case AndInt32:
       case OrInt32:
       case AndInt64:
@@ -1485,7 +1485,7 @@ private:
       case LeUInt64:
       case GeSInt64:
       case GeUInt64:
-        return LiteralUtils::makeFromInt32(1, i32, *getModule());
+        return LiteralUtils::makeFromInt32(1, Type::i32, *getModule());
       default:
         return nullptr;
     }
diff --git a/src/passes/PostAssemblyScript.cpp b/src/passes/PostAssemblyScript.cpp
index 4e41c8f08..eeb077ce9 100644
--- a/src/passes/PostAssemblyScript.cpp
+++ b/src/passes/PostAssemblyScript.cpp
@@ -88,8 +88,8 @@ struct AliasGraph : LocalGraph {
 // consider a full retain pattern, which must also set a local.
 static bool isRetainCall(Call* expr) {
   // __retain(...)
-  return expr->target == RETAIN && expr->type == i32 &&
-         expr->operands.size() == 1 && expr->operands[0]->type == i32;
+  return expr->target == RETAIN && expr->type == Type::i32 &&
+         expr->operands.size() == 1 && expr->operands[0]->type == Type::i32;
 }
 
 // Tests if a local.set is considered to be a full retain pattern.
@@ -117,8 +117,8 @@ static bool isRetainLocation(Expression** expr) {
 // consider a full release pattern, which must also get a local.
 static bool isReleaseCall(Call* expr) {
   // __release(...)
-  return expr->target == RELEASE && expr->type == none &&
-         expr->operands.size() == 1 && expr->operands[0]->type == i32;
+  return expr->target == RELEASE && expr->type == Type::none &&
+         expr->operands.size() == 1 && expr->operands[0]->type == Type::i32;
 }
 
 // Tests if the given location is that of a full release pattern. Note that
@@ -138,7 +138,7 @@ static bool isReleaseLocation(Expression** expr) {
 // Tests if the given call calls any allocation function.
 static bool isAllocCall(Call* expr) {
   return (expr->target == ALLOC || expr->target == ALLOCARRAY) &&
-         expr->type == i32;
+         expr->type == Type::i32;
 }
 
 // A pass that eliminates redundant retain and release calls.
diff --git a/src/passes/Precompute.cpp b/src/passes/Precompute.cpp
index 85eb026f9..21393c1cf 100644
--- a/src/passes/Precompute.cpp
+++ b/src/passes/Precompute.cpp
@@ -199,7 +199,7 @@ struct Precompute
         // this expression causes a return. if it's already a return, reuse the
         // node
         if (auto* ret = curr->dynCast<Return>()) {
-          if (flow.value.type != none) {
+          if (flow.value.type != Type::none) {
             // reuse a const value if there is one
             if (ret->value) {
               if (auto* value = ret->value->dynCast<Const>()) {
@@ -226,7 +226,7 @@ struct Precompute
       if (auto* br = curr->dynCast<Break>()) {
         br->name = flow.breakTo;
         br->condition = nullptr;
-        if (flow.value.type != none) {
+        if (flow.value.type != Type::none) {
           // reuse a const value if there is one
           if (br->value) {
             if (auto* value = br->value->dynCast<Const>()) {
@@ -243,10 +243,11 @@ struct Precompute
         br->finalize();
       } else {
         Builder builder(*getModule());
-        replaceCurrent(builder.makeBreak(
-          flow.breakTo,
-          flow.value.type != none ? builder.makeConstExpression(flow.value)
-                                  : nullptr));
+        replaceCurrent(
+          builder.makeBreak(flow.breakTo,
+                            flow.value.type != Type::none
+                              ? builder.makeConstExpression(flow.value)
+                              : nullptr));
       }
       return;
     }
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 549aa661d..106966ef1 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -89,7 +89,9 @@ std::ostream& operator<<(std::ostream& os, SigName sigName) {
 
 // Printing "unreachable" as a instruction prefix type is not valid in wasm text
 // format. Print something else to make it pass.
-static Type forceConcrete(Type type) { return type.isConcrete() ? type : i32; }
+static Type forceConcrete(Type type) {
+  return type.isConcrete() ? type : Type::i32;
+}
 
 // Prints the internal contents of an expression: everything but
 // the children.
@@ -186,7 +188,8 @@ struct PrintExpressionContents
       o << ".atomic";
     }
     o << ".load";
-    if (curr->type != unreachable && curr->bytes < curr->type.getByteSize()) {
+    if (curr->type != Type::unreachable &&
+        curr->bytes < curr->type.getByteSize()) {
       if (curr->bytes == 1) {
         o << '8';
       } else if (curr->bytes == 2) {
@@ -212,7 +215,7 @@ struct PrintExpressionContents
       o << ".atomic";
     }
     o << ".store";
-    if (curr->bytes < 4 || (curr->valueType == i64 && curr->bytes < 8)) {
+    if (curr->bytes < 4 || (curr->valueType == Type::i64 && curr->bytes < 8)) {
       if (curr->bytes == 1) {
         o << '8';
       } else if (curr->bytes == 2) {
@@ -233,7 +236,7 @@ struct PrintExpressionContents
   }
   static void printRMWSize(std::ostream& o, Type type, uint8_t bytes) {
     prepareColor(o) << forceConcrete(type) << ".atomic.rmw";
-    if (type != unreachable && bytes != type.getByteSize()) {
+    if (type != Type::unreachable && bytes != type.getByteSize()) {
       if (bytes == 1) {
         o << '8';
       } else if (bytes == 2) {
@@ -269,7 +272,8 @@ struct PrintExpressionContents
         o << "xchg";
         break;
     }
-    if (curr->type != unreachable && curr->bytes != curr->type.getByteSize()) {
+    if (curr->type != Type::unreachable &&
+        curr->bytes != curr->type.getByteSize()) {
       o << "_u";
     }
     restoreNormalColor(o);
@@ -281,7 +285,8 @@ struct PrintExpressionContents
     prepareColor(o);
     printRMWSize(o, curr->type, curr->bytes);
     o << "cmpxchg";
-    if (curr->type != unreachable && curr->bytes != curr->type.getByteSize()) {
+    if (curr->type != Type::unreachable &&
+        curr->bytes != curr->type.getByteSize()) {
       o << "_u";
     }
     restoreNormalColor(o);
diff --git a/src/passes/ReReloop.cpp b/src/passes/ReReloop.cpp
index 53a232dc1..8f83f8a8f 100644
--- a/src/passes/ReReloop.cpp
+++ b/src/passes/ReReloop.cpp
@@ -320,7 +320,7 @@ struct ReReloop final : public Pass {
     // anywhere. add a return as needed
     for (auto* cfgBlock : relooper->Blocks) {
       auto* block = cfgBlock->Code->cast<Block>();
-      if (cfgBlock->BranchesOut.empty() && block->type != unreachable) {
+      if (cfgBlock->BranchesOut.empty() && block->type != Type::unreachable) {
         block->list.push_back(function->sig.results == Type::none
                                 ? (Expression*)builder->makeReturn()
                                 : (Expression*)builder->makeUnreachable());
@@ -345,7 +345,7 @@ struct ReReloop final : public Pass {
     relooper->Calculate(entry);
     // render
     {
-      auto temp = builder->addVar(function, i32);
+      auto temp = builder->addVar(function, Type::i32);
       CFG::RelooperBuilder builder(*module, temp);
       function->body = relooper->Render(builder);
       // if the function has a result, and the relooper emitted
diff --git a/src/passes/RemoveNonJSOps.cpp b/src/passes/RemoveNonJSOps.cpp
index eebd97ae1..d758440f2 100644
--- a/src/passes/RemoveNonJSOps.cpp
+++ b/src/passes/RemoveNonJSOps.cpp
@@ -158,12 +158,12 @@ struct RemoveNonJSOpsPass : public WalkerPass<PostWalker<RemoveNonJSOpsPass>> {
     // can actually implement) and then use reinterpretation to get the float
     // back out.
     switch (curr->type) {
-      case f32:
-        curr->type = i32;
+      case Type::f32:
+        curr->type = Type::i32;
         replaceCurrent(builder->makeUnary(ReinterpretInt32, curr));
         break;
-      case f64:
-        curr->type = i64;
+      case Type::f64:
+        curr->type = Type::i64;
         replaceCurrent(builder->makeUnary(ReinterpretInt64, curr));
         break;
       default:
@@ -180,12 +180,12 @@ struct RemoveNonJSOpsPass : public WalkerPass<PostWalker<RemoveNonJSOpsPass>> {
     // we can actually implement) and then use reinterpretation to store the
     // right value.
     switch (curr->valueType) {
-      case f32:
-        curr->valueType = i32;
+      case Type::f32:
+        curr->valueType = Type::i32;
         curr->value = builder->makeUnary(ReinterpretFloat32, curr->value);
         break;
-      case f64:
-        curr->valueType = i64;
+      case Type::f64:
+        curr->valueType = Type::i64;
         curr->value = builder->makeUnary(ReinterpretFloat64, curr->value);
         break;
       default:
diff --git a/src/passes/RemoveUnusedBrs.cpp b/src/passes/RemoveUnusedBrs.cpp
index e0174934a..786fcaf67 100644
--- a/src/passes/RemoveUnusedBrs.cpp
+++ b/src/passes/RemoveUnusedBrs.cpp
@@ -37,7 +37,7 @@ static bool canTurnIfIntoBrIf(Expression* ifCondition,
                               Expression* brValue,
                               PassOptions& options) {
   // if the if isn't even reached, this is all dead code anyhow
-  if (ifCondition->type == unreachable) {
+  if (ifCondition->type == Type::unreachable) {
     return false;
   }
   if (!brValue) {
@@ -104,7 +104,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
       flows.push_back(currp);
     } else if (curr->is<If>()) {
       auto* iff = curr->cast<If>();
-      if (iff->condition->type == unreachable) {
+      if (iff->condition->type == Type::unreachable) {
         // avoid trying to optimize this, we never reach it anyhow
         self->stopFlow();
         return;
@@ -118,7 +118,8 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         // there is no way to emit a proper type for one arm being
         // none and the other flowing a value; and there is no way
         // to flow a value from a none.
-        if (iff->ifTrue->type == none || iff->ifFalse->type == none) {
+        if (iff->ifTrue->type == Type::none ||
+            iff->ifFalse->type == Type::none) {
           self->removeValueFlow(ifTrueFlows);
           self->stopValueFlow();
         }
@@ -166,7 +167,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
       // invalid to represent as such.
       auto size = list.size();
       for (Index i = 0; i < size; i++) {
-        if (i != size - 1 && list[i]->type == unreachable) {
+        if (i != size - 1 && list[i]->type == Type::unreachable) {
           // No value flows out of this block.
           self->stopValueFlow();
           break;
@@ -283,17 +284,18 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         }
         // great, we are in that case, optimize
         Builder builder(*getModule());
-        auto temp = builder.addVar(getFunction(), i32);
+        auto temp = builder.addVar(getFunction(), Type::i32);
         Expression* z;
         replaceCurrent(
           z = builder.makeIf(
-            builder.makeLocalTee(temp, curr->condition, i32),
-            builder.makeIf(builder.makeBinary(EqInt32,
-                                              builder.makeLocalGet(temp, i32),
-                                              builder.makeConst(Literal(int32_t(
-                                                curr->targets.size() - 1)))),
-                           builder.makeBreak(curr->targets.back()),
-                           builder.makeBreak(curr->default_)),
+            builder.makeLocalTee(temp, curr->condition, Type::i32),
+            builder.makeIf(
+              builder.makeBinary(
+                EqInt32,
+                builder.makeLocalGet(temp, Type::i32),
+                builder.makeConst(Literal(int32_t(curr->targets.size() - 1)))),
+              builder.makeBreak(curr->targets.back()),
+              builder.makeBreak(curr->default_)),
             builder.makeBreak(curr->targets.front())));
       }
     }
@@ -318,7 +320,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             // avoid one branch.
             // If running the br's condition unconditionally is too expensive,
             // give up.
-            auto* zero = LiteralUtils::makeZero(i32, *getModule());
+            auto* zero = LiteralUtils::makeZero(Type::i32, *getModule());
             if (tooCostlyToRunUnconditionally(
                   getPassOptions(), br->condition, zero)) {
               return;
@@ -353,7 +355,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
     auto* iff = (*currp)->dynCast<If>();
 
     if (iff) {
-      if (iff->condition->type == unreachable) {
+      if (iff->condition->type == Type::unreachable) {
         // avoid trying to optimize this, we never reach it anyhow
         return;
       }
@@ -424,7 +426,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         if (!iff->ifFalse) {
           // we need the ifTrue to break, so it cannot reach the code we want to
           // move
-          if (iff->ifTrue->type == unreachable) {
+          if (iff->ifTrue->type == Type::unreachable) {
             iff->ifFalse = builder.stealSlice(block, i + 1, list.size());
             iff->finalize();
             block->finalize();
@@ -468,13 +470,13 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             return block;
           };
 
-          if (iff->ifTrue->type == unreachable) {
+          if (iff->ifTrue->type == Type::unreachable) {
             iff->ifFalse = blockifyMerge(
               iff->ifFalse, builder.stealSlice(block, i + 1, list.size()));
             iff->finalize();
             block->finalize();
             return true;
-          } else if (iff->ifFalse->type == unreachable) {
+          } else if (iff->ifFalse->type == Type::unreachable) {
             iff->ifTrue = blockifyMerge(
               iff->ifTrue, builder.stealSlice(block, i + 1, list.size()));
             iff->finalize();
@@ -781,7 +783,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             auto* br1 = list[i]->dynCast<Break>();
             // avoid unreachable brs, as they are dead code anyhow, and after
             // merging them the outer scope could need type changes
-            if (!br1 || !br1->condition || br1->type == unreachable) {
+            if (!br1 || !br1->condition || br1->type == Type::unreachable) {
               continue;
             }
             assert(!br1->value);
@@ -792,7 +794,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
             assert(!br2->value); // same target as previous, which has no value
             // a br_if and then a br[_if] with the same target right after it
             if (br2->condition) {
-              if (shrink && br2->type != unreachable) {
+              if (shrink && br2->type != Type::unreachable) {
                 // Join adjacent br_ifs to the same target, making one br_if
                 // with a "selectified" condition that executes both.
                 if (!EffectAnalyzer(passOptions, br2->condition)
@@ -872,7 +874,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
           // type is unreachable that means it is not actually reached, which we
           // can ignore.
           if (br && br->condition && br->name == curr->name &&
-              br->type != unreachable) {
+              br->type != Type::unreachable) {
             if (BranchUtils::BranchSeeker::count(curr, curr->name) == 1) {
               // no other breaks to that name, so we can do this
               if (!drop) {
@@ -977,7 +979,8 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
         }
         auto tryToOptimize =
           [&](Expression* one, Expression* two, bool flipCondition) {
-            if (one->type == unreachable && two->type != unreachable) {
+            if (one->type == Type::unreachable &&
+                two->type != Type::unreachable) {
               if (auto* br = one->dynCast<Break>()) {
                 if (ExpressionAnalyzer::isSimple(br)) {
                   // Wonderful, do it!
@@ -1130,7 +1133,7 @@ struct RemoveUnusedBrs : public WalkerPass<PostWalker<RemoveUnusedBrs>> {
           if (!br->condition || br->value) {
             return nullptr;
           }
-          if (br->type != none) {
+          if (br->type != Type::none) {
             // no value, so can be unreachable or none. ignore unreachable ones,
             // dce will clean it up
             return nullptr;
diff --git a/src/passes/SafeHeap.cpp b/src/passes/SafeHeap.cpp
index fc6706f3e..a9ad62820 100644
--- a/src/passes/SafeHeap.cpp
+++ b/src/passes/SafeHeap.cpp
@@ -71,7 +71,7 @@ struct AccessInstrumenter : public WalkerPass<PostWalker<AccessInstrumenter>> {
   AccessInstrumenter* create() override { return new AccessInstrumenter; }
 
   void visitLoad(Load* curr) {
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       return;
     }
     Builder builder(*getModule());
@@ -85,7 +85,7 @@ struct AccessInstrumenter : public WalkerPass<PostWalker<AccessInstrumenter>> {
   }
 
   void visitStore(Store* curr) {
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       return;
     }
     Builder builder(*getModule());
@@ -96,7 +96,7 @@ struct AccessInstrumenter : public WalkerPass<PostWalker<AccessInstrumenter>> {
                          builder.makeConst(Literal(int32_t(curr->offset))),
                          curr->value,
                        },
-                       none));
+                       Type::none));
   }
 };
 
@@ -169,15 +169,16 @@ struct SafeHeap : public Pass {
   void addGlobals(Module* module, FeatureSet features) {
     // load funcs
     Load load;
-    for (auto type : {i32, i64, f32, f64, v128}) {
-      if (type == v128 && !features.hasSIMD()) {
+    for (Type type : {Type::i32, Type::i64, Type::f32, Type::f64, Type::v128}) {
+      if (type == Type::v128 && !features.hasSIMD()) {
         continue;
       }
       load.type = type;
       for (Index bytes : {1, 2, 4, 8, 16}) {
         load.bytes = bytes;
-        if (bytes > type.getByteSize() || (type == f32 && bytes != 4) ||
-            (type == f64 && bytes != 8) || (type == v128 && bytes != 16)) {
+        if (bytes > type.getByteSize() || (type == Type::f32 && bytes != 4) ||
+            (type == Type::f64 && bytes != 8) ||
+            (type == Type::v128 && bytes != 16)) {
           continue;
         }
         for (auto signed_ : {true, false}) {
@@ -204,18 +205,19 @@ struct SafeHeap : public Pass {
     }
     // store funcs
     Store store;
-    for (auto valueType : {i32, i64, f32, f64, v128}) {
-      if (valueType == v128 && !features.hasSIMD()) {
+    for (Type valueType :
+         {Type::i32, Type::i64, Type::f32, Type::f64, Type::v128}) {
+      if (valueType == Type::v128 && !features.hasSIMD()) {
         continue;
       }
       store.valueType = valueType;
-      store.type = none;
+      store.type = Type::none;
       for (Index bytes : {1, 2, 4, 8, 16}) {
         store.bytes = bytes;
         if (bytes > valueType.getByteSize() ||
-            (valueType == f32 && bytes != 4) ||
-            (valueType == f64 && bytes != 8) ||
-            (valueType == v128 && bytes != 16)) {
+            (valueType == Type::f32 && bytes != 4) ||
+            (valueType == Type::f64 && bytes != 8) ||
+            (valueType == Type::v128 && bytes != 16)) {
           continue;
         }
         for (Index align : {1, 2, 4, 8, 16}) {
@@ -246,13 +248,14 @@ struct SafeHeap : public Pass {
     func->name = name;
     // pointer, offset
     func->sig = Signature({Type::i32, Type::i32}, style.type);
-    func->vars.push_back(i32);   // pointer + offset
+    func->vars.push_back(Type::i32); // pointer + offset
     Builder builder(*module);
     auto* block = builder.makeBlock();
     block->list.push_back(builder.makeLocalSet(
       2,
-      builder.makeBinary(
-        AddInt32, builder.makeLocalGet(0, i32), builder.makeLocalGet(1, i32))));
+      builder.makeBinary(AddInt32,
+                         builder.makeLocalGet(0, Type::i32),
+                         builder.makeLocalGet(1, Type::i32))));
     // check for reading past valid memory: if pointer + offset + bytes
     block->list.push_back(makeBoundsCheck(style.type, builder, 2, style.bytes));
     // check proper alignment
@@ -262,7 +265,7 @@ struct SafeHeap : public Pass {
     // do the load
     auto* load = module->allocator.alloc<Load>();
     *load = style; // basically the same as the template we are given!
-    load->ptr = builder.makeLocalGet(2, i32);
+    load->ptr = builder.makeLocalGet(2, Type::i32);
     Expression* last = load;
     if (load->isAtomic && load->signed_) {
       // atomic loads cannot be signed, manually sign it
@@ -285,13 +288,14 @@ struct SafeHeap : public Pass {
     func->name = name;
     // pointer, offset, value
     func->sig = Signature({Type::i32, Type::i32, style.valueType}, Type::none);
-    func->vars.push_back(i32);               // pointer + offset
+    func->vars.push_back(Type::i32); // pointer + offset
     Builder builder(*module);
     auto* block = builder.makeBlock();
     block->list.push_back(builder.makeLocalSet(
       3,
-      builder.makeBinary(
-        AddInt32, builder.makeLocalGet(0, i32), builder.makeLocalGet(1, i32))));
+      builder.makeBinary(AddInt32,
+                         builder.makeLocalGet(0, Type::i32),
+                         builder.makeLocalGet(1, Type::i32))));
     // check for reading past valid memory: if pointer + offset + bytes
     block->list.push_back(
       makeBoundsCheck(style.valueType, builder, 3, style.bytes));
@@ -302,10 +306,10 @@ struct SafeHeap : public Pass {
     // do the store
     auto* store = module->allocator.alloc<Store>();
     *store = style; // basically the same as the template we are given!
-    store->ptr = builder.makeLocalGet(3, i32);
+    store->ptr = builder.makeLocalGet(3, Type::i32);
     store->value = builder.makeLocalGet(2, style.valueType);
     block->list.push_back(store);
-    block->finalize(none);
+    block->finalize(Type::none);
     func->body = block;
     module->addFunction(func);
   }
@@ -313,9 +317,9 @@ struct SafeHeap : public Pass {
   Expression* makeAlignCheck(Address align, Builder& builder, Index local) {
     return builder.makeIf(
       builder.makeBinary(AndInt32,
-                         builder.makeLocalGet(local, i32),
+                         builder.makeLocalGet(local, Type::i32),
                          builder.makeConst(Literal(int32_t(align - 1)))),
-      builder.makeCall(alignfault, {}, none));
+      builder.makeCall(alignfault, {}, Type::none));
   }
 
   Expression*
@@ -324,30 +328,30 @@ struct SafeHeap : public Pass {
     auto upperBound = options.lowMemoryUnused ? PassOptions::LowMemoryBound : 0;
     Expression* brkLocation;
     if (sbrk.is()) {
-      brkLocation =
-        builder.makeCall(sbrk, {builder.makeConst(Literal(int32_t(0)))}, i32);
+      brkLocation = builder.makeCall(
+        sbrk, {builder.makeConst(Literal(int32_t(0)))}, Type::i32);
     } else {
       Expression* sbrkPtr;
       if (dynamicTopPtr.is()) {
-        sbrkPtr = builder.makeGlobalGet(dynamicTopPtr, i32);
+        sbrkPtr = builder.makeGlobalGet(dynamicTopPtr, Type::i32);
       } else {
-        sbrkPtr = builder.makeCall(getSbrkPtr, {}, i32);
+        sbrkPtr = builder.makeCall(getSbrkPtr, {}, Type::i32);
       }
-      brkLocation = builder.makeLoad(4, false, 0, 4, sbrkPtr, i32);
+      brkLocation = builder.makeLoad(4, false, 0, 4, sbrkPtr, Type::i32);
     }
     return builder.makeIf(
       builder.makeBinary(
         OrInt32,
         builder.makeBinary(upperOp,
-                           builder.makeLocalGet(local, i32),
+                           builder.makeLocalGet(local, Type::i32),
                            builder.makeConst(Literal(int32_t(upperBound)))),
         builder.makeBinary(
           GtUInt32,
           builder.makeBinary(AddInt32,
-                             builder.makeLocalGet(local, i32),
+                             builder.makeLocalGet(local, Type::i32),
                              builder.makeConst(Literal(int32_t(bytes)))),
           brkLocation)),
-      builder.makeCall(segfault, {}, none));
+      builder.makeCall(segfault, {}, Type::none));
   }
 };
 
diff --git a/src/passes/SimplifyLocals.cpp b/src/passes/SimplifyLocals.cpp
index a952f8a38..f7558aa83 100644
--- a/src/passes/SimplifyLocals.cpp
+++ b/src/passes/SimplifyLocals.cpp
@@ -421,7 +421,7 @@ struct SimplifyLocals
   void optimizeLoopReturn(Loop* loop) {
     // If there is a sinkable thing in an eligible loop, we can optimize
     // it in a trivial way to the outside of the loop.
-    if (loop->type != none) {
+    if (loop->type != Type::none) {
       return;
     }
     if (sinkables.empty()) {
@@ -442,7 +442,7 @@ struct SimplifyLocals
     block->list[block->list.size() - 1] = set->value;
     *item = builder.makeNop();
     block->finalize();
-    assert(block->type != none);
+    assert(block->type != Type::none);
     loop->finalize();
     set->value = loop;
     set->finalize();
@@ -584,7 +584,7 @@ struct SimplifyLocals
     assert(iff->ifFalse);
     // if this if already has a result, or is unreachable code, we have
     // nothing to do
-    if (iff->type != none) {
+    if (iff->type != Type::none) {
       return;
     }
     // We now have the sinkables from both sides of the if, and can look
@@ -606,14 +606,16 @@ struct SimplifyLocals
     Sinkables& ifFalse = sinkables;
     Index goodIndex = -1;
     bool found = false;
-    if (iff->ifTrue->type == unreachable) {
-      assert(iff->ifFalse->type != unreachable); // since the if type is none
+    if (iff->ifTrue->type == Type::unreachable) {
+      // since the if type is none
+      assert(iff->ifFalse->type != Type::unreachable);
       if (!ifFalse.empty()) {
         goodIndex = ifFalse.begin()->first;
         found = true;
       }
-    } else if (iff->ifFalse->type == unreachable) {
-      assert(iff->ifTrue->type != unreachable); // since the if type is none
+    } else if (iff->ifFalse->type == Type::unreachable) {
+      // since the if type is none
+      assert(iff->ifTrue->type != Type::unreachable);
       if (!ifTrue.empty()) {
         goodIndex = ifTrue.begin()->first;
         found = true;
@@ -636,7 +638,7 @@ struct SimplifyLocals
     // ensure we have a place to write the return values for, if not, we
     // need another cycle
     auto* ifTrueBlock = iff->ifTrue->dynCast<Block>();
-    if (iff->ifTrue->type != unreachable) {
+    if (iff->ifTrue->type != Type::unreachable) {
       if (!ifTrueBlock || ifTrueBlock->name.is() ||
           ifTrueBlock->list.size() == 0 ||
           !ifTrueBlock->list.back()->is<Nop>()) {
@@ -645,7 +647,7 @@ struct SimplifyLocals
       }
     }
     auto* ifFalseBlock = iff->ifFalse->dynCast<Block>();
-    if (iff->ifFalse->type != unreachable) {
+    if (iff->ifFalse->type != Type::unreachable) {
       if (!ifFalseBlock || ifFalseBlock->name.is() ||
           ifFalseBlock->list.size() == 0 ||
           !ifFalseBlock->list.back()->is<Nop>()) {
@@ -654,24 +656,24 @@ struct SimplifyLocals
       }
     }
     // all set, go
-    if (iff->ifTrue->type != unreachable) {
+    if (iff->ifTrue->type != Type::unreachable) {
       auto* ifTrueItem = ifTrue.at(goodIndex).item;
       ifTrueBlock->list[ifTrueBlock->list.size() - 1] =
         (*ifTrueItem)->template cast<LocalSet>()->value;
       ExpressionManipulator::nop(*ifTrueItem);
       ifTrueBlock->finalize();
-      assert(ifTrueBlock->type != none);
+      assert(ifTrueBlock->type != Type::none);
     }
-    if (iff->ifFalse->type != unreachable) {
+    if (iff->ifFalse->type != Type::unreachable) {
       auto* ifFalseItem = ifFalse.at(goodIndex).item;
       ifFalseBlock->list[ifFalseBlock->list.size() - 1] =
         (*ifFalseItem)->template cast<LocalSet>()->value;
       ExpressionManipulator::nop(*ifFalseItem);
       ifFalseBlock->finalize();
-      assert(ifFalseBlock->type != none);
+      assert(ifFalseBlock->type != Type::none);
     }
     iff->finalize(); // update type
-    assert(iff->type != none);
+    assert(iff->type != Type::none);
     // finally, create a local.set on the iff itself
     auto* newLocalSet =
       Builder(*this->getModule()).makeLocalSet(goodIndex, iff);
@@ -703,7 +705,7 @@ struct SimplifyLocals
   // arm into a one-sided if.
   void optimizeIfReturn(If* iff, Expression** currp) {
     // If this if is unreachable code, we have nothing to do.
-    if (iff->type != none || iff->ifTrue->type != none) {
+    if (iff->type != Type::none || iff->ifTrue->type != Type::none) {
       return;
     }
     // Anything sinkable is good for us.
@@ -726,14 +728,14 @@ struct SimplifyLocals
     ifTrueBlock->list[ifTrueBlock->list.size() - 1] = set->value;
     *item = builder.makeNop();
     ifTrueBlock->finalize();
-    assert(ifTrueBlock->type != none);
+    assert(ifTrueBlock->type != Type::none);
     // Update the ifFalse side.
     iff->ifFalse = builder.makeLocalGet(
       set->index, this->getFunction()->getLocalType(set->index));
     iff->finalize(); // update type
     // Update the get count.
     getCounter.num[set->index]++;
-    assert(iff->type != none);
+    assert(iff->type != Type::none);
     // Finally, reuse the local.set on the iff itself.
     set->value = iff;
     set->finalize();
diff --git a/src/passes/SpillPointers.cpp b/src/passes/SpillPointers.cpp
index 7458f5fbd..453510592 100644
--- a/src/passes/SpillPointers.cpp
+++ b/src/passes/SpillPointers.cpp
@@ -155,7 +155,7 @@ struct SpillPointers
                                Function* func,
                                Module* module) {
     auto* call = *origin;
-    if (call->type == unreachable) {
+    if (call->type == Type::unreachable) {
       return; // the call is never reached anyhow, ignore
     }
     Builder builder(*module);
diff --git a/src/passes/StackIR.cpp b/src/passes/StackIR.cpp
index e4aa55d68..a628468fb 100644
--- a/src/passes/StackIR.cpp
+++ b/src/passes/StackIR.cpp
@@ -88,7 +88,7 @@ private:
           // We can remove this.
           removeAt(i);
         }
-      } else if (inst->type == unreachable) {
+      } else if (inst->type == Type::unreachable) {
         inUnreachableCode = true;
       }
     }
@@ -221,7 +221,7 @@ private:
           // This is an actual regular value on the value stack.
           values.push_back(null);
         }
-      } else if (inst->origin->is<LocalSet>() && inst->type == none) {
+      } else if (inst->origin->is<LocalSet>() && inst->type == Type::none) {
         // This set is potentially optimizable later, add to stack.
         values.push_back(i);
       }
diff --git a/src/passes/TrapMode.cpp b/src/passes/TrapMode.cpp
index 9c855d8c1..f3cf3c63c 100644
--- a/src/passes/TrapMode.cpp
+++ b/src/passes/TrapMode.cpp
@@ -99,7 +99,7 @@ bool isTruncOpSigned(UnaryOp op) {
 Function* generateBinaryFunc(Module& wasm, Binary* curr) {
   BinaryOp op = curr->op;
   Type type = curr->type;
-  bool isI64 = type == i64;
+  bool isI64 = type == Type::i64;
   Builder builder(wasm);
   Expression* result = builder.makeBinary(
     op, builder.makeLocalGet(0, type), builder.makeLocalGet(1, type));
@@ -145,7 +145,7 @@ Function* generateUnaryFunc(Module& wasm, Unary* curr) {
   Type type = curr->value->type;
   Type retType = curr->type;
   UnaryOp truncOp = curr->op;
-  bool isF64 = type == f64;
+  bool isF64 = type == Type::f64;
 
   Builder builder(wasm);
 
@@ -276,12 +276,12 @@ Expression* makeTrappingUnary(Unary* curr,
   // slow ffi If i64, there is no "JS" way to handle this, as no i64s in JS, so
   // always clamp if we don't allow traps asm.js doesn't have unsigned
   // f64-to-int, so just use the signed one.
-  if (curr->type != i64 && mode == TrapMode::JS) {
+  if (curr->type != Type::i64 && mode == TrapMode::JS) {
     // WebAssembly traps on float-to-int overflows, but asm.js wouldn't, so we
     // must emulate that
     ensureF64ToI64JSImport(trappingFunctions);
     Expression* f64Value = ensureDouble(curr->value, wasm.allocator);
-    return builder.makeCall(F64_TO_INT, {f64Value}, i32);
+    return builder.makeCall(F64_TO_INT, {f64Value}, Type::i32);
   }
 
   ensureUnaryFunc(curr, wasm, trappingFunctions);
diff --git a/src/passes/Untee.cpp b/src/passes/Untee.cpp
index 6e5fb489b..848e88a65 100644
--- a/src/passes/Untee.cpp
+++ b/src/passes/Untee.cpp
@@ -35,7 +35,7 @@ struct Untee : public WalkerPass<PostWalker<Untee>> {
 
   void visitLocalSet(LocalSet* curr) {
     if (curr->isTee()) {
-      if (curr->value->type == unreachable) {
+      if (curr->value->type == Type::unreachable) {
         // we don't reach the tee, just remove it
         replaceCurrent(curr->value);
       } else {
diff --git a/src/passes/Vacuum.cpp b/src/passes/Vacuum.cpp
index 48a55ed89..a222b0159 100644
--- a/src/passes/Vacuum.cpp
+++ b/src/passes/Vacuum.cpp
@@ -56,7 +56,7 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
   Expression* optimize(Expression* curr, bool resultUsed, bool typeMatters) {
     auto type = curr->type;
     // An unreachable node must not be changed.
-    if (type == unreachable) {
+    if (type == Type::unreachable) {
       return curr;
     }
     // We iterate on possible replacements. If a replacement changes the type,
@@ -226,7 +226,7 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
           // example, code-folding can merge out identical zeros at the end of
           // if arms).
           optimized = LiteralUtils::makeZero(child->type, *getModule());
-        } else if (child->type == unreachable) {
+        } else if (child->type == Type::unreachable) {
           // Don't try to optimize out an unreachable child (dce can do that
           // properly).
           optimized = child;
@@ -245,7 +245,7 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
           list[z] = nullptr;
         }
         // if this is unreachable, the rest is dead code
-        if (list[z - skip]->type == unreachable && z < size - 1) {
+        if (list[z - skip]->type == Type::unreachable && z < size - 1) {
           for (Index i = z - skip + 1; i < list.size(); i++) {
             auto* remove = list[i];
             if (remove) {
@@ -292,7 +292,7 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
       return;
     }
     // if the condition is unreachable, just return it
-    if (curr->condition->type == unreachable) {
+    if (curr->condition->type == Type::unreachable) {
       typeUpdater.noteRecursiveRemoval(curr->ifTrue);
       if (curr->ifFalse) {
         typeUpdater.noteRecursiveRemoval(curr->ifFalse);
@@ -366,14 +366,14 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
             BranchUtils::BranchSeeker seeker(block->name);
             Expression* temp = block;
             seeker.walk(temp);
-            if (seeker.found && seeker.valueType != none) {
+            if (seeker.found && seeker.valueType != Type::none) {
               canPop = false;
             }
           }
           if (canPop) {
             block->list.back() = last;
             block->list.pop_back();
-            block->type = none;
+            block->type = Type::none;
             // we don't need the drop anymore, let's see what we have left in
             // the block
             if (block->list.size() > 1) {
@@ -394,16 +394,17 @@ struct Vacuum : public WalkerPass<ExpressionStackWalker<Vacuum>> {
     auto* iff = curr->value->dynCast<If>();
     if (iff && iff->ifFalse && iff->type.isConcrete()) {
       // reuse the drop in both cases
-      if (iff->ifTrue->type == unreachable && iff->ifFalse->type.isConcrete()) {
+      if (iff->ifTrue->type == Type::unreachable &&
+          iff->ifFalse->type.isConcrete()) {
         curr->value = iff->ifFalse;
         iff->ifFalse = curr;
-        iff->type = none;
+        iff->type = Type::none;
         replaceCurrent(iff);
-      } else if (iff->ifFalse->type == unreachable &&
+      } else if (iff->ifFalse->type == Type::unreachable &&
                  iff->ifTrue->type.isConcrete()) {
         curr->value = iff->ifTrue;
         iff->ifTrue = curr;
-        iff->type = none;
+        iff->type = Type::none;
         replaceCurrent(iff);
       }
     }
diff --git a/src/shell-interface.h b/src/shell-interface.h
index 75f8e81b8..cd5e5210b 100644
--- a/src/shell-interface.h
+++ b/src/shell-interface.h
@@ -100,28 +100,28 @@ struct ShellExternalInterface : ModuleInstance::ExternalInterface {
     ModuleUtils::iterImportedGlobals(wasm, [&](Global* import) {
       if (import->module == SPECTEST && import->base.startsWith(GLOBAL)) {
         switch (import->type) {
-          case i32:
+          case Type::i32:
             globals[import->name] = Literal(int32_t(666));
             break;
-          case i64:
+          case Type::i64:
             globals[import->name] = Literal(int64_t(666));
             break;
-          case f32:
+          case Type::f32:
             globals[import->name] = Literal(float(666.6));
             break;
-          case f64:
+          case Type::f64:
             globals[import->name] = Literal(double(666.6));
             break;
-          case v128:
+          case Type::v128:
             assert(false && "v128 not implemented yet");
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
             globals[import->name] = Literal::makeNullref();
             break;
-          case none:
-          case unreachable:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
       }
diff --git a/src/tools/asm2wasm.cpp b/src/tools/asm2wasm.cpp
index b54dd8cd8..6b20d1bcb 100644
--- a/src/tools/asm2wasm.cpp
+++ b/src/tools/asm2wasm.cpp
@@ -227,7 +227,7 @@ int main(int argc, const char* argv[]) {
     Expression* init;
     const auto& memBase = options.extra.find("mem base");
     if (memBase == options.extra.end()) {
-      init = Builder(wasm).makeGlobalGet(MEMORY_BASE, i32);
+      init = Builder(wasm).makeGlobalGet(MEMORY_BASE, Type::i32);
     } else {
       init = Builder(wasm).makeConst(
         Literal(int32_t(atoi(memBase->second.c_str()))));
diff --git a/src/tools/fuzzing.h b/src/tools/fuzzing.h
index af5773e80..81bd87581 100644
--- a/src/tools/fuzzing.h
+++ b/src/tools/fuzzing.h
@@ -378,16 +378,20 @@ private:
           builder.makeBinary(
             AddInt32,
             builder.makeBinary(ShlInt32,
-                               builder.makeLocalGet(0, i32),
+                               builder.makeLocalGet(0, Type::i32),
                                builder.makeConst(Literal(uint32_t(5)))),
-            builder.makeLocalGet(0, i32)),
-          builder.makeLoad(
-            1, false, i, 1, builder.makeConst(Literal(uint32_t(0))), i32))));
-    }
-    contents.push_back(builder.makeLocalGet(0, i32));
+            builder.makeLocalGet(0, Type::i32)),
+          builder.makeLoad(1,
+                           false,
+                           i,
+                           1,
+                           builder.makeConst(Literal(uint32_t(0))),
+                           Type::i32))));
+    }
+    contents.push_back(builder.makeLocalGet(0, Type::i32));
     auto* body = builder.makeBlock(contents);
     auto* hasher = wasm.addFunction(builder.makeFunction(
-      "hashMemory", Signature(Type::none, Type::i32), {i32}, body));
+      "hashMemory", Signature(Type::none, Type::i32), {Type::i32}, body));
     wasm.addExport(
       builder.makeExport(hasher->name, hasher->name, ExternalKind::Function));
     // Export memory so JS fuzzing can use it
@@ -446,7 +450,7 @@ private:
   void addHangLimitSupport() {
     auto* glob =
       builder.makeGlobal(HANG_LIMIT_GLOBAL,
-                         i32,
+                         Type::i32,
                          builder.makeConst(Literal(int32_t(HANG_LIMIT))),
                          Builder::Mutable);
     wasm.addGlobal(glob);
@@ -481,12 +485,12 @@ private:
     return builder.makeSequence(
       builder.makeIf(
         builder.makeUnary(UnaryOp::EqZInt32,
-                          builder.makeGlobalGet(HANG_LIMIT_GLOBAL, i32)),
-        makeTrivial(unreachable)),
+                          builder.makeGlobalGet(HANG_LIMIT_GLOBAL, Type::i32)),
+        makeTrivial(Type::unreachable)),
       builder.makeGlobalSet(
         HANG_LIMIT_GLOBAL,
         builder.makeBinary(BinaryOp::SubInt32,
-                           builder.makeGlobalGet(HANG_LIMIT_GLOBAL, i32),
+                           builder.makeGlobalGet(HANG_LIMIT_GLOBAL, Type::i32),
                            builder.makeConst(Literal(int32_t(1))))));
   }
 
@@ -502,18 +506,18 @@ private:
         builder.makeConst(literal));
       wasm.addFunction(func);
     };
-    add("deNan32", f32, Literal(float(0)), EqFloat32);
-    add("deNan64", f64, Literal(double(0)), EqFloat64);
+    add("deNan32", Type::f32, Literal(float(0)), EqFloat32);
+    add("deNan64", Type::f64, Literal(double(0)), EqFloat64);
   }
 
   Expression* makeDeNanOp(Expression* expr) {
     if (allowNaNs) {
       return expr;
     }
-    if (expr->type == f32) {
-      return builder.makeCall("deNan32", {expr}, f32);
-    } else if (expr->type == f64) {
-      return builder.makeCall("deNan64", {expr}, f64);
+    if (expr->type == Type::f32) {
+      return builder.makeCall("deNan32", {expr}, Type::f32);
+    } else if (expr->type == Type::f64) {
+      return builder.makeCall("deNan64", {expr}, Type::f64);
     }
     return expr; // unreachable etc. is fine
   }
@@ -558,7 +562,7 @@ private:
     // with small chance, make the body unreachable
     auto bodyType = func->sig.results;
     if (oneIn(10)) {
-      bodyType = unreachable;
+      bodyType = Type::unreachable;
     }
     // with reasonable chance make the body a block
     if (oneIn(2)) {
@@ -844,34 +848,34 @@ private:
         } else {
           return makeLocalGet(type);
         }
-      } else if (type == none) {
+      } else if (type == Type::none) {
         if (oneIn(2)) {
           return makeNop(type);
         } else {
           return makeLocalSet(type);
         }
       }
-      assert(type == unreachable);
+      assert(type == Type::unreachable);
       return makeTrivial(type);
     }
     nesting++;
     Expression* ret = nullptr;
     switch (type) {
-      case i32:
-      case i64:
-      case f32:
-      case f64:
-      case v128:
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
+      case Type::i32:
+      case Type::i64:
+      case Type::f32:
+      case Type::f64:
+      case Type::v128:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
         ret = _makeConcrete(type);
         break;
-      case none:
+      case Type::none:
         ret = _makenone();
         break;
-      case unreachable:
+      case Type::unreachable:
         ret = _makeunreachable();
         break;
     }
@@ -942,19 +946,19 @@ private:
     }
     choice = upTo(100);
     if (choice < 50) {
-      return makeLocalSet(none);
+      return makeLocalSet(Type::none);
     }
     if (choice < 60) {
-      return makeBlock(none);
+      return makeBlock(Type::none);
     }
     if (choice < 70) {
-      return makeIf(none);
+      return makeIf(Type::none);
     }
     if (choice < 80) {
-      return makeLoop(none);
+      return makeLoop(Type::none);
     }
     if (choice < 90) {
-      return makeBreak(none);
+      return makeBreak(Type::none);
     }
     using Self = TranslateToFuzzReader;
     auto options = FeatureOptions<Expression* (Self::*)(Type)>()
@@ -972,41 +976,41 @@ private:
                           &Self::makeGlobalSet)
                      .add(FeatureSet::BulkMemory, &Self::makeBulkMemory)
                      .add(FeatureSet::Atomics, &Self::makeAtomic);
-    return (this->*pick(options))(none);
+    return (this->*pick(options))(Type::none);
   }
 
   Expression* _makeunreachable() {
     switch (upTo(15)) {
       case 0:
-        return makeBlock(unreachable);
+        return makeBlock(Type::unreachable);
       case 1:
-        return makeIf(unreachable);
+        return makeIf(Type::Type::unreachable);
       case 2:
-        return makeLoop(unreachable);
+        return makeLoop(Type::unreachable);
       case 3:
-        return makeBreak(unreachable);
+        return makeBreak(Type::unreachable);
       case 4:
-        return makeCall(unreachable);
+        return makeCall(Type::unreachable);
       case 5:
-        return makeCallIndirect(unreachable);
+        return makeCallIndirect(Type::unreachable);
       case 6:
-        return makeLocalSet(unreachable);
+        return makeLocalSet(Type::unreachable);
       case 7:
-        return makeStore(unreachable);
+        return makeStore(Type::unreachable);
       case 8:
-        return makeUnary(unreachable);
+        return makeUnary(Type::unreachable);
       case 9:
-        return makeBinary(unreachable);
+        return makeBinary(Type::unreachable);
       case 10:
-        return makeSelect(unreachable);
+        return makeSelect(Type::unreachable);
       case 11:
-        return makeSwitch(unreachable);
+        return makeSwitch(Type::unreachable);
       case 12:
-        return makeDrop(unreachable);
+        return makeDrop(Type::unreachable);
       case 13:
-        return makeReturn(unreachable);
+        return makeReturn(Type::unreachable);
       case 14:
-        return makeUnreachable(unreachable);
+        return makeUnreachable(Type::unreachable);
     }
     WASM_UNREACHABLE("unexpected value");
   }
@@ -1019,10 +1023,10 @@ private:
       } else {
         return makeConst(type);
       }
-    } else if (type == none) {
+    } else if (type == Type::none) {
       return makeNop(type);
     }
-    assert(type == unreachable);
+    assert(type == Type::unreachable);
     Expression* ret = nullptr;
     if (func->sig.results.isConcrete()) {
       ret = makeTrivial(func->sig.results);
@@ -1051,13 +1055,13 @@ private:
       num++;
     }
     while (num > 0 && !finishedInput) {
-      ret->list.push_back(make(none));
+      ret->list.push_back(make(Type::none));
       num--;
     }
     // give a chance to make the final element an unreachable break, instead
     // of concrete - a common pattern (branch to the top of a loop etc.)
     if (!finishedInput && type.isConcrete() && oneIn(2)) {
-      ret->list.push_back(makeBreak(unreachable));
+      ret->list.push_back(makeBreak(Type::unreachable));
     } else {
       ret->list.push_back(make(type));
     }
@@ -1069,8 +1073,8 @@ private:
     }
     if (ret->type != type) {
       // e.g. we might want an unreachable block, but a child breaks to it
-      assert(type == unreachable && ret->type == none);
-      return builder.makeSequence(ret, make(unreachable));
+      assert(type == Type::unreachable && ret->type == Type::none);
+      return builder.makeSequence(ret, make(Type::unreachable));
     }
     return ret;
   }
@@ -1087,7 +1091,7 @@ private:
     } else {
       // ensure a branch back. also optionally create some loop vars
       std::vector<Expression*> list;
-      list.push_back(makeMaybeBlock(none)); // primary contents
+      list.push_back(makeMaybeBlock(Type::none)); // primary contents
       // possible branch back
       list.push_back(builder.makeBreak(ret->name, nullptr, makeCondition()));
       list.push_back(make(type)); // final element, so we have the right type
@@ -1103,7 +1107,7 @@ private:
     // we want a 50-50 chance for the condition to be taken, for interesting
     // execution paths. by itself, there is bias (e.g. most consts are "yes")
     // so even that out with noise
-    auto* ret = make(i32);
+    auto* ret = make(Type::i32);
     if (oneIn(2)) {
       ret = builder.makeUnary(UnaryOp::EqZInt32, ret);
     }
@@ -1138,7 +1142,7 @@ private:
       return makeTrivial(type);
     }
     Expression* condition = nullptr;
-    if (type != unreachable) {
+    if (type != Type::unreachable) {
       hangStack.push_back(nullptr);
       condition = makeCondition();
     }
@@ -1157,8 +1161,8 @@ private:
         auto* ret = builder.makeBreak(name, make(type), condition);
         hangStack.pop_back();
         return ret;
-      } else if (type == none) {
-        if (valueType != none) {
+      } else if (type == Type::none) {
+        if (valueType != Type::Type::none) {
           // we need to break to a proper place
           continue;
         }
@@ -1166,8 +1170,8 @@ private:
         hangStack.pop_back();
         return ret;
       } else {
-        assert(type == unreachable);
-        if (valueType != none) {
+        assert(type == Type::unreachable);
+        if (valueType != Type::Type::none) {
           // we need to break to a proper place
           continue;
         }
@@ -1210,7 +1214,7 @@ private:
       }
     }
     // we failed to find something
-    if (type != unreachable) {
+    if (type != Type::unreachable) {
       hangStack.pop_back();
     }
     return makeTrivial(type);
@@ -1254,7 +1258,7 @@ private:
     while (1) {
       // TODO: handle unreachable
       targetFn = wasm.getFunction(data[i]);
-      isReturn = type == unreachable && wasm.features.hasTailCall() &&
+      isReturn = type == Type::unreachable && wasm.features.hasTailCall() &&
                  func->sig.results == targetFn->sig.results;
       if (targetFn->sig.results == type || isReturn) {
         break;
@@ -1273,7 +1277,7 @@ private:
     if (!allowOOB || !oneIn(10)) {
       target = builder.makeConst(Literal(int32_t(i)));
     } else {
-      target = make(i32);
+      target = make(Type::i32);
     }
     std::vector<Expression*> args;
     for (auto type : targetFn->sig.params.expand()) {
@@ -1291,7 +1295,7 @@ private:
   }
 
   Expression* makeLocalSet(Type type) {
-    bool tee = type != none;
+    bool tee = type != Type::none;
     Type valueType;
     if (tee) {
       valueType = type;
@@ -1319,18 +1323,18 @@ private:
   }
 
   Expression* makeGlobalSet(Type type) {
-    assert(type == none);
+    assert(type == Type::none);
     type = getConcreteType();
     auto& globals = globalsByType[type];
     if (globals.empty()) {
-      return makeTrivial(none);
+      return makeTrivial(Type::Type::none);
     }
     auto* value = make(type);
     return builder.makeGlobalSet(pick(globals), value);
   }
 
   Expression* makePointer() {
-    auto* ret = make(i32);
+    auto* ret = make(Type::i32);
     // with high probability, mask the pointer so it's in a reasonable
     // range. otherwise, most pointers are going to be out of range and
     // most memory ops will just trap
@@ -1345,7 +1349,7 @@ private:
     auto offset = logify(get());
     auto ptr = makePointer();
     switch (type) {
-      case i32: {
+      case Type::i32: {
         bool signed_ = get() & 1;
         switch (upTo(3)) {
           case 0:
@@ -1358,7 +1362,7 @@ private:
         }
         WASM_UNREACHABLE("unexpected value");
       }
-      case i64: {
+      case Type::i64: {
         bool signed_ = get() & 1;
         switch (upTo(4)) {
           case 0:
@@ -1374,25 +1378,25 @@ private:
         }
         WASM_UNREACHABLE("unexpected value");
       }
-      case f32: {
+      case Type::f32: {
         return builder.makeLoad(4, false, offset, pick(1, 2, 4), ptr, type);
       }
-      case f64: {
+      case Type::f64: {
         return builder.makeLoad(8, false, offset, pick(1, 2, 4, 8), ptr, type);
       }
-      case v128: {
+      case Type::v128: {
         if (!wasm.features.hasSIMD()) {
           return makeTrivial(type);
         }
         return builder.makeLoad(
           16, false, offset, pick(1, 2, 4, 8, 16), ptr, type);
       }
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("invalid type");
     }
     WASM_UNREACHABLE("invalid type");
@@ -1404,7 +1408,7 @@ private:
       return makeTrivial(type);
     }
     auto* ret = makeNonAtomicLoad(type);
-    if (type != i32 && type != i64) {
+    if (type != Type::i32 && type != Type::i64) {
       return ret;
     }
     if (!wasm.features.hasAtomics() || oneIn(2)) {
@@ -1420,7 +1424,7 @@ private:
   }
 
   Expression* makeNonAtomicStore(Type type) {
-    if (type == unreachable) {
+    if (type == Type::unreachable) {
       // make a normal store, then make it unreachable
       auto* ret = makeNonAtomicStore(getStorableType());
       auto* store = ret->dynCast<Store>();
@@ -1429,14 +1433,14 @@ private:
       }
       switch (upTo(3)) {
         case 0:
-          store->ptr = make(unreachable);
+          store->ptr = make(Type::unreachable);
           break;
         case 1:
-          store->value = make(unreachable);
+          store->value = make(Type::unreachable);
           break;
         case 2:
-          store->ptr = make(unreachable);
-          store->value = make(unreachable);
+          store->ptr = make(Type::unreachable);
+          store->value = make(Type::unreachable);
           break;
       }
       store->finalize();
@@ -1444,14 +1448,14 @@ private:
     }
     // the type is none or unreachable. we also need to pick the value
     // type.
-    if (type == none) {
+    if (type == Type::none) {
       type = getStorableType();
     }
     auto offset = logify(get());
     auto ptr = makePointer();
     auto value = make(type);
     switch (type) {
-      case i32: {
+      case Type::i32: {
         switch (upTo(3)) {
           case 0:
             return builder.makeStore(1, offset, 1, ptr, value, type);
@@ -1463,7 +1467,7 @@ private:
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case i64: {
+      case Type::i64: {
         switch (upTo(4)) {
           case 0:
             return builder.makeStore(1, offset, 1, ptr, value, type);
@@ -1478,25 +1482,25 @@ private:
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case f32: {
+      case Type::f32: {
         return builder.makeStore(4, offset, pick(1, 2, 4), ptr, value, type);
       }
-      case f64: {
+      case Type::f64: {
         return builder.makeStore(8, offset, pick(1, 2, 4, 8), ptr, value, type);
       }
-      case v128: {
+      case Type::v128: {
         if (!wasm.features.hasSIMD()) {
           return makeTrivial(type);
         }
         return builder.makeStore(
           16, offset, pick(1, 2, 4, 8, 16), ptr, value, type);
       }
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("invalid type");
     }
     WASM_UNREACHABLE("invalid type");
@@ -1511,7 +1515,7 @@ private:
     if (!store) {
       return ret;
     }
-    if (store->value->type != i32 && store->value->type != i64) {
+    if (store->value->type != Type::i32 && store->value->type != Type::i64) {
       return store;
     }
     if (!wasm.features.hasAtomics() || oneIn(2)) {
@@ -1525,51 +1529,51 @@ private:
   }
 
   Literal makeArbitraryLiteral(Type type) {
-    if (type == v128) {
+    if (type == Type::v128) {
       // generate each lane individually for random lane interpretation
       switch (upTo(6)) {
         case 0:
-          return Literal(std::array<Literal, 16>{{makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32),
-                                                  makeLiteral(i32)}});
+          return Literal(std::array<Literal, 16>{{makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32),
+                                                  makeLiteral(Type::i32)}});
         case 1:
-          return Literal(std::array<Literal, 8>{{makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32)}});
+          return Literal(std::array<Literal, 8>{{makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32)}});
         case 2:
-          return Literal(std::array<Literal, 4>{{makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32),
-                                                 makeLiteral(i32)}});
+          return Literal(std::array<Literal, 4>{{makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32),
+                                                 makeLiteral(Type::i32)}});
         case 3:
-          return Literal(
-            std::array<Literal, 2>{{makeLiteral(i64), makeLiteral(i64)}});
+          return Literal(std::array<Literal, 2>{
+            {makeLiteral(Type::i64), makeLiteral(Type::i64)}});
         case 4:
-          return Literal(std::array<Literal, 4>{{makeLiteral(f32),
-                                                 makeLiteral(f32),
-                                                 makeLiteral(f32),
-                                                 makeLiteral(f32)}});
+          return Literal(std::array<Literal, 4>{{makeLiteral(Type::f32),
+                                                 makeLiteral(Type::f32),
+                                                 makeLiteral(Type::f32),
+                                                 makeLiteral(Type::f32)}});
         case 5:
-          return Literal(
-            std::array<Literal, 2>{{makeLiteral(f64), makeLiteral(f64)}});
+          return Literal(std::array<Literal, 2>{
+            {makeLiteral(Type::f64), makeLiteral(Type::f64)}});
         default:
           WASM_UNREACHABLE("unexpected value");
       }
@@ -1579,21 +1583,21 @@ private:
       case 0: {
         // totally random, entire range
         switch (type) {
-          case i32:
+          case Type::i32:
             return Literal(get32());
-          case i64:
+          case Type::i64:
             return Literal(get64());
-          case f32:
+          case Type::f32:
             return Literal(getFloat());
-          case f64:
+          case Type::f64:
             return Literal(getDouble());
-          case v128:
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
-          case none:
-          case unreachable:
+          case Type::v128:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("invalid type");
         }
         break;
@@ -1624,21 +1628,21 @@ private:
             WASM_UNREACHABLE("invalid value");
         }
         switch (type) {
-          case i32:
+          case Type::i32:
             return Literal(int32_t(small));
-          case i64:
+          case Type::i64:
             return Literal(int64_t(small));
-          case f32:
+          case Type::f32:
             return Literal(float(small));
-          case f64:
+          case Type::f64:
             return Literal(double(small));
-          case v128:
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
-          case none:
-          case unreachable:
+          case Type::v128:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
         break;
@@ -1647,7 +1651,7 @@ private:
         // special values
         Literal value;
         switch (type) {
-          case i32:
+          case Type::i32:
             value =
               Literal(pick<int32_t>(0,
                                     std::numeric_limits<int8_t>::min(),
@@ -1660,7 +1664,7 @@ private:
                                     std::numeric_limits<uint16_t>::max(),
                                     std::numeric_limits<uint32_t>::max()));
             break;
-          case i64:
+          case Type::i64:
             value =
               Literal(pick<int64_t>(0,
                                     std::numeric_limits<int8_t>::min(),
@@ -1676,7 +1680,7 @@ private:
                                     std::numeric_limits<uint32_t>::max(),
                                     std::numeric_limits<uint64_t>::max()));
             break;
-          case f32:
+          case Type::f32:
             value = Literal(pick<float>(0,
                                         std::numeric_limits<float>::min(),
                                         std::numeric_limits<float>::max(),
@@ -1687,7 +1691,7 @@ private:
                                         std::numeric_limits<uint32_t>::max(),
                                         std::numeric_limits<uint64_t>::max()));
             break;
-          case f64:
+          case Type::f64:
             value = Literal(pick<double>(0,
                                          std::numeric_limits<float>::min(),
                                          std::numeric_limits<float>::max(),
@@ -1700,13 +1704,13 @@ private:
                                          std::numeric_limits<uint32_t>::max(),
                                          std::numeric_limits<uint64_t>::max()));
             break;
-          case v128:
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
-          case none:
-          case unreachable:
+          case Type::v128:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
         // tweak around special values
@@ -1722,25 +1726,25 @@ private:
         // powers of 2
         Literal value;
         switch (type) {
-          case i32:
+          case Type::i32:
             value = Literal(int32_t(1) << upTo(32));
             break;
-          case i64:
+          case Type::i64:
             value = Literal(int64_t(1) << upTo(64));
             break;
-          case f32:
+          case Type::f32:
             value = Literal(float(int64_t(1) << upTo(64)));
             break;
-          case f64:
+          case Type::f64:
             value = Literal(double(int64_t(1) << upTo(64)));
             break;
-          case v128:
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
-          case none:
-          case unreachable:
+          case Type::v128:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
         // maybe negative
@@ -1790,9 +1794,10 @@ private:
   }
 
   Expression* makeUnary(Type type) {
-    if (type == unreachable) {
+    if (type == Type::unreachable) {
       if (auto* unary = makeUnary(getConcreteType())->dynCast<Unary>()) {
-        return makeDeNanOp(builder.makeUnary(unary->op, make(unreachable)));
+        return makeDeNanOp(
+          builder.makeUnary(unary->op, make(Type::unreachable)));
       }
       // give up
       return makeTrivial(type);
@@ -1803,18 +1808,18 @@ private:
     }
 
     switch (type) {
-      case i32: {
+      case Type::i32: {
         switch (getConcreteType()) {
-          case i32: {
+          case Type::i32: {
             auto op = pick(
               FeatureOptions<UnaryOp>()
                 .add(FeatureSet::MVP, EqZInt32, ClzInt32, CtzInt32, PopcntInt32)
                 .add(FeatureSet::SignExt, ExtendS8Int32, ExtendS16Int32));
-            return buildUnary({op, make(i32)});
+            return buildUnary({op, make(Type::i32)});
           }
-          case i64:
-            return buildUnary({pick(EqZInt64, WrapInt64), make(i64)});
-          case f32: {
+          case Type::i64:
+            return buildUnary({pick(EqZInt64, WrapInt64), make(Type::i64)});
+          case Type::f32: {
             auto op = pick(FeatureOptions<UnaryOp>()
                              .add(FeatureSet::MVP,
                                   TruncSFloat32ToInt32,
@@ -1823,9 +1828,9 @@ private:
                              .add(FeatureSet::TruncSat,
                                   TruncSatSFloat32ToInt32,
                                   TruncSatUFloat32ToInt32));
-            return buildUnary({op, make(f32)});
+            return buildUnary({op, make(Type::f32)});
           }
-          case f64: {
+          case Type::f64: {
             auto op = pick(FeatureOptions<UnaryOp>()
                              .add(FeatureSet::MVP,
                                   TruncSFloat64ToInt32,
@@ -1833,9 +1838,9 @@ private:
                              .add(FeatureSet::TruncSat,
                                   TruncSatSFloat64ToInt32,
                                   TruncSatUFloat64ToInt32));
-            return buildUnary({op, make(f64)});
+            return buildUnary({op, make(Type::f64)});
           }
-          case v128: {
+          case Type::v128: {
             assert(wasm.features.hasSIMD());
             return buildUnary({pick(AnyTrueVecI8x16,
                                     AllTrueVecI8x16,
@@ -1845,20 +1850,20 @@ private:
                                     AllTrueVecI32x4,
                                     AnyTrueVecI64x2,
                                     AllTrueVecI64x2),
-                               make(v128)});
+                               make(Type::v128)});
           }
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
             return makeTrivial(type);
-          case none:
-          case unreachable:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
         WASM_UNREACHABLE("invalid type");
       }
-      case i64: {
+      case Type::i64: {
         switch (upTo(4)) {
           case 0: {
             auto op =
@@ -1868,10 +1873,11 @@ private:
                           ExtendS8Int64,
                           ExtendS16Int64,
                           ExtendS32Int64));
-            return buildUnary({op, make(i64)});
+            return buildUnary({op, make(Type::i64)});
           }
           case 1:
-            return buildUnary({pick(ExtendSInt32, ExtendUInt32), make(i32)});
+            return buildUnary(
+              {pick(ExtendSInt32, ExtendUInt32), make(Type::i32)});
           case 2: {
             auto op = pick(FeatureOptions<UnaryOp>()
                              .add(FeatureSet::MVP,
@@ -1880,7 +1886,7 @@ private:
                              .add(FeatureSet::TruncSat,
                                   TruncSatSFloat32ToInt64,
                                   TruncSatUFloat32ToInt64));
-            return buildUnary({op, make(f32)});
+            return buildUnary({op, make(Type::f32)});
           }
           case 3: {
             auto op = pick(FeatureOptions<UnaryOp>()
@@ -1891,12 +1897,12 @@ private:
                              .add(FeatureSet::TruncSat,
                                   TruncSatSFloat64ToInt64,
                                   TruncSatUFloat64ToInt64));
-            return buildUnary({op, make(f64)});
+            return buildUnary({op, make(Type::f64)});
           }
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case f32: {
+      case Type::f32: {
         switch (upTo(4)) {
           case 0:
             return makeDeNanOp(buildUnary({pick(NegFloat32,
@@ -1906,22 +1912,22 @@ private:
                                                 TruncFloat32,
                                                 NearestFloat32,
                                                 SqrtFloat32),
-                                           make(f32)}));
+                                           make(Type::f32)}));
           case 1:
             return makeDeNanOp(buildUnary({pick(ConvertUInt32ToFloat32,
                                                 ConvertSInt32ToFloat32,
                                                 ReinterpretInt32),
-                                           make(i32)}));
+                                           make(Type::i32)}));
           case 2:
             return makeDeNanOp(
               buildUnary({pick(ConvertUInt64ToFloat32, ConvertSInt64ToFloat32),
-                          make(i64)}));
+                          make(Type::i64)}));
           case 3:
-            return makeDeNanOp(buildUnary({DemoteFloat64, make(f64)}));
+            return makeDeNanOp(buildUnary({DemoteFloat64, make(Type::f64)}));
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case f64: {
+      case Type::f64: {
         switch (upTo(4)) {
           case 0:
             return makeDeNanOp(buildUnary({pick(NegFloat64,
@@ -1931,33 +1937,34 @@ private:
                                                 TruncFloat64,
                                                 NearestFloat64,
                                                 SqrtFloat64),
-                                           make(f64)}));
+                                           make(Type::f64)}));
           case 1:
             return makeDeNanOp(
               buildUnary({pick(ConvertUInt32ToFloat64, ConvertSInt32ToFloat64),
-                          make(i32)}));
+                          make(Type::i32)}));
           case 2:
             return makeDeNanOp(buildUnary({pick(ConvertUInt64ToFloat64,
                                                 ConvertSInt64ToFloat64,
                                                 ReinterpretInt64),
-                                           make(i64)}));
+                                           make(Type::i64)}));
           case 3:
-            return makeDeNanOp(buildUnary({PromoteFloat32, make(f32)}));
+            return makeDeNanOp(buildUnary({PromoteFloat32, make(Type::f32)}));
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case v128: {
+      case Type::v128: {
         assert(wasm.features.hasSIMD());
         switch (upTo(5)) {
           case 0:
             return buildUnary(
-              {pick(SplatVecI8x16, SplatVecI16x8, SplatVecI32x4), make(i32)});
+              {pick(SplatVecI8x16, SplatVecI16x8, SplatVecI32x4),
+               make(Type::i32)});
           case 1:
-            return buildUnary({SplatVecI64x2, make(i64)});
+            return buildUnary({SplatVecI64x2, make(Type::i64)});
           case 2:
-            return buildUnary({SplatVecF32x4, make(f32)});
+            return buildUnary({SplatVecF32x4, make(Type::f32)});
           case 3:
-            return buildUnary({SplatVecF64x2, make(f64)});
+            return buildUnary({SplatVecF64x2, make(Type::f64)});
           case 4:
             return buildUnary({pick(NotVec128,
                                     NegVecI8x16,
@@ -1986,16 +1993,16 @@ private:
                                     WidenHighSVecI16x8ToVecI32x4,
                                     WidenLowUVecI16x8ToVecI32x4,
                                     WidenHighUVecI16x8ToVecI32x4),
-                               make(v128)});
+                               make(Type::v128)});
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
     WASM_UNREACHABLE("invalid type");
@@ -2006,10 +2013,10 @@ private:
   }
 
   Expression* makeBinary(Type type) {
-    if (type == unreachable) {
+    if (type == Type::unreachable) {
       if (auto* binary = makeBinary(getConcreteType())->dynCast<Binary>()) {
-        return makeDeNanOp(
-          buildBinary({binary->op, make(unreachable), make(unreachable)}));
+        return makeDeNanOp(buildBinary(
+          {binary->op, make(Type::unreachable), make(Type::unreachable)}));
       }
       // give up
       return makeTrivial(type);
@@ -2020,7 +2027,7 @@ private:
     }
 
     switch (type) {
-      case i32: {
+      case Type::i32: {
         switch (upTo(4)) {
           case 0:
             return buildBinary({pick(AddInt32,
@@ -2048,8 +2055,8 @@ private:
                                      GtUInt32,
                                      GeSInt32,
                                      GeUInt32),
-                                make(i32),
-                                make(i32)});
+                                make(Type::i32),
+                                make(Type::i32)});
           case 1:
             return buildBinary({pick(EqInt64,
                                      NeInt64,
@@ -2061,8 +2068,8 @@ private:
                                      GtUInt64,
                                      GeSInt64,
                                      GeUInt64),
-                                make(i64),
-                                make(i64)});
+                                make(Type::i64),
+                                make(Type::i64)});
           case 2:
             return buildBinary({pick(EqFloat32,
                                      NeFloat32,
@@ -2070,8 +2077,8 @@ private:
                                      LeFloat32,
                                      GtFloat32,
                                      GeFloat32),
-                                make(f32),
-                                make(f32)});
+                                make(Type::f32),
+                                make(Type::f32)});
           case 3:
             return buildBinary({pick(EqFloat64,
                                      NeFloat64,
@@ -2079,12 +2086,12 @@ private:
                                      LeFloat64,
                                      GtFloat64,
                                      GeFloat64),
-                                make(f64),
-                                make(f64)});
+                                make(Type::f64),
+                                make(Type::f64)});
         }
         WASM_UNREACHABLE("invalid value");
       }
-      case i64: {
+      case Type::i64: {
         return buildBinary({pick(AddInt64,
                                  SubInt64,
                                  MulInt64,
@@ -2100,10 +2107,10 @@ private:
                                  ShrSInt64,
                                  RotLInt64,
                                  RotRInt64),
-                            make(i64),
-                            make(i64)});
+                            make(Type::i64),
+                            make(Type::i64)});
       }
-      case f32: {
+      case Type::f32: {
         return makeDeNanOp(buildBinary({pick(AddFloat32,
                                              SubFloat32,
                                              MulFloat32,
@@ -2111,10 +2118,10 @@ private:
                                              CopySignFloat32,
                                              MinFloat32,
                                              MaxFloat32),
-                                        make(f32),
-                                        make(f32)}));
+                                        make(Type::f32),
+                                        make(Type::f32)}));
       }
-      case f64: {
+      case Type::f64: {
         return makeDeNanOp(buildBinary({pick(AddFloat64,
                                              SubFloat64,
                                              MulFloat64,
@@ -2122,10 +2129,10 @@ private:
                                              CopySignFloat64,
                                              MinFloat64,
                                              MaxFloat64),
-                                        make(f64),
-                                        make(f64)}));
+                                        make(Type::f64),
+                                        make(Type::f64)}));
       }
-      case v128: {
+      case Type::v128: {
         assert(wasm.features.hasSIMD());
         return buildBinary({pick(EqVecI8x16,
                                  NeVecI8x16,
@@ -2222,15 +2229,15 @@ private:
                                  NarrowSVecI32x4ToVecI16x8,
                                  NarrowUVecI32x4ToVecI16x8,
                                  SwizzleVec8x16),
-                            make(v128),
-                            make(v128)});
-      }
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+                            make(Type::v128),
+                            make(Type::v128)});
+      }
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
     WASM_UNREACHABLE("invalid type");
@@ -2244,18 +2251,18 @@ private:
     Type subType1 = pick(getSubTypes(type));
     Type subType2 = pick(getSubTypes(type));
     return makeDeNanOp(
-      buildSelect({make(i32), make(subType1), make(subType2)}, type));
+      buildSelect({make(Type::i32), make(subType1), make(subType2)}, type));
   }
 
   Expression* makeSwitch(Type type) {
-    assert(type == unreachable);
+    assert(type == Type::unreachable);
     if (breakableStack.empty()) {
       return make(type);
     }
     // we need to find proper targets to break to; try a bunch
     int tries = TRIES;
     std::vector<Name> names;
-    Type valueType = unreachable;
+    Type valueType = Type::Type::unreachable;
     while (tries-- > 0) {
       auto* target = pick(breakableStack);
       auto name = getTargetName(target);
@@ -2275,14 +2282,14 @@ private:
     }
     auto default_ = names.back();
     names.pop_back();
-    auto temp1 = make(i32),
+    auto temp1 = make(Type::i32),
          temp2 = valueType.isConcrete() ? make(valueType) : nullptr;
     return builder.makeSwitch(names, default_, temp1, temp2);
   }
 
   Expression* makeDrop(Type type) {
     return builder.makeDrop(
-      make(type == unreachable ? type : getConcreteType()));
+      make(type == Type::unreachable ? type : getConcreteType()));
   }
 
   Expression* makeReturn(Type type) {
@@ -2291,12 +2298,12 @@ private:
   }
 
   Expression* makeNop(Type type) {
-    assert(type == none);
+    assert(type == Type::none);
     return builder.makeNop();
   }
 
   Expression* makeUnreachable(Type type) {
-    assert(type == unreachable);
+    assert(type == Type::unreachable);
     return builder.makeUnreachable();
   }
 
@@ -2306,26 +2313,26 @@ private:
       return makeTrivial(type);
     }
     wasm.memory.shared = true;
-    if (type == none) {
+    if (type == Type::none) {
       return builder.makeAtomicFence();
     }
-    if (type == i32 && oneIn(2)) {
+    if (type == Type::i32 && oneIn(2)) {
       if (ATOMIC_WAITS && oneIn(2)) {
         auto* ptr = makePointer();
-        auto expectedType = pick(i32, i64);
+        auto expectedType = pick(Type::i32, Type::i64);
         auto* expected = make(expectedType);
-        auto* timeout = make(i64);
+        auto* timeout = make(Type::i64);
         return builder.makeAtomicWait(
           ptr, expected, timeout, expectedType, logify(get()));
       } else {
         auto* ptr = makePointer();
-        auto* count = make(i32);
+        auto* count = make(Type::i32);
         return builder.makeAtomicNotify(ptr, count, logify(get()));
       }
     }
     Index bytes;
     switch (type) {
-      case i32: {
+      case Type::i32: {
         switch (upTo(3)) {
           case 0:
             bytes = 1;
@@ -2341,7 +2348,7 @@ private:
         }
         break;
       }
-      case i64: {
+      case Type::i64: {
         switch (upTo(4)) {
           case 0:
             bytes = 1;
@@ -2391,14 +2398,14 @@ private:
     if (type.isRef()) {
       return makeTrivial(type);
     }
-    if (type != v128) {
+    if (type != Type::v128) {
       return makeSIMDExtract(type);
     }
     switch (upTo(7)) {
       case 0:
-        return makeUnary(v128);
+        return makeUnary(Type::v128);
       case 1:
-        return makeBinary(v128);
+        return makeBinary(Type::v128);
       case 2:
         return makeSIMDReplace();
       case 3:
@@ -2416,32 +2423,32 @@ private:
   Expression* makeSIMDExtract(Type type) {
     auto op = static_cast<SIMDExtractOp>(0);
     switch (type) {
-      case i32:
+      case Type::i32:
         op = pick(ExtractLaneSVecI8x16,
                   ExtractLaneUVecI8x16,
                   ExtractLaneSVecI16x8,
                   ExtractLaneUVecI16x8,
                   ExtractLaneVecI32x4);
         break;
-      case i64:
+      case Type::i64:
         op = ExtractLaneVecI64x2;
         break;
-      case f32:
+      case Type::f32:
         op = ExtractLaneVecF32x4;
         break;
-      case f64:
+      case Type::f64:
         op = ExtractLaneVecF64x2;
         break;
-      case v128:
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+      case Type::v128:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
-    Expression* vec = make(v128);
+    Expression* vec = make(Type::v128);
     uint8_t index = 0;
     switch (op) {
       case ExtractLaneSVecI8x16:
@@ -2471,33 +2478,33 @@ private:
                             ReplaceLaneVecI64x2,
                             ReplaceLaneVecF32x4,
                             ReplaceLaneVecF64x2);
-    Expression* vec = make(v128);
+    Expression* vec = make(Type::v128);
     uint8_t index;
     Type lane_t;
     switch (op) {
       case ReplaceLaneVecI8x16:
         index = upTo(16);
-        lane_t = i32;
+        lane_t = Type::i32;
         break;
       case ReplaceLaneVecI16x8:
         index = upTo(8);
-        lane_t = i32;
+        lane_t = Type::i32;
         break;
       case ReplaceLaneVecI32x4:
         index = upTo(4);
-        lane_t = i32;
+        lane_t = Type::i32;
         break;
       case ReplaceLaneVecI64x2:
         index = upTo(2);
-        lane_t = i64;
+        lane_t = Type::i64;
         break;
       case ReplaceLaneVecF32x4:
         index = upTo(4);
-        lane_t = f32;
+        lane_t = Type::f32;
         break;
       case ReplaceLaneVecF64x2:
         index = upTo(2);
-        lane_t = f64;
+        lane_t = Type::f64;
         break;
       default:
         WASM_UNREACHABLE("unexpected op");
@@ -2507,8 +2514,8 @@ private:
   }
 
   Expression* makeSIMDShuffle() {
-    Expression* left = make(v128);
-    Expression* right = make(v128);
+    Expression* left = make(Type::v128);
+    Expression* right = make(Type::v128);
     std::array<uint8_t, 16> mask;
     for (size_t i = 0; i < 16; ++i) {
       mask[i] = upTo(32);
@@ -2524,9 +2531,9 @@ private:
     //                         QFMAF64x2,
     //                         QFMSF64x2);
     SIMDTernaryOp op = Bitselect;
-    Expression* a = make(v128);
-    Expression* b = make(v128);
-    Expression* c = make(v128);
+    Expression* a = make(Type::v128);
+    Expression* b = make(Type::v128);
+    Expression* c = make(Type::v128);
     return builder.makeSIMDTernary(op, a, b, c);
   }
 
@@ -2543,8 +2550,8 @@ private:
                           ShlVecI64x2,
                           ShrSVecI64x2,
                           ShrUVecI64x2);
-    Expression* vec = make(v128);
-    Expression* shift = make(i32);
+    Expression* vec = make(Type::v128);
+    Expression* shift = make(Type::Type::i32);
     return builder.makeSIMDShift(op, vec, shift);
   }
 
@@ -2590,7 +2597,7 @@ private:
       return makeTrivial(type);
     }
     assert(wasm.features.hasBulkMemory());
-    assert(type == none);
+    assert(type == Type::none);
     switch (upTo(4)) {
       case 0:
         return makeMemoryInit();
@@ -2618,7 +2625,7 @@ private:
 
   Expression* makeMemoryInit() {
     if (!allowMemory) {
-      return makeTrivial(none);
+      return makeTrivial(Type::none);
     }
     uint32_t segment = upTo(wasm.memory.segments.size());
     size_t totalSize = wasm.memory.segments[segment].data.size();
@@ -2632,28 +2639,28 @@ private:
 
   Expression* makeDataDrop() {
     if (!allowMemory) {
-      return makeTrivial(none);
+      return makeTrivial(Type::none);
     }
     return builder.makeDataDrop(upTo(wasm.memory.segments.size()));
   }
 
   Expression* makeMemoryCopy() {
     if (!allowMemory) {
-      return makeTrivial(none);
+      return makeTrivial(Type::none);
     }
     Expression* dest = makePointer();
     Expression* source = makePointer();
-    Expression* size = make(i32);
+    Expression* size = make(Type::i32);
     return builder.makeMemoryCopy(dest, source, size);
   }
 
   Expression* makeMemoryFill() {
     if (!allowMemory) {
-      return makeTrivial(none);
+      return makeTrivial(Type::none);
     }
     Expression* dest = makePointer();
     Expression* value = makePointer();
-    Expression* size = make(i32);
+    Expression* size = make(Type::i32);
     return builder.makeMemoryFill(dest, value, size);
   }
 
@@ -2662,12 +2669,12 @@ private:
   Expression* makeLogging() {
     auto type = getLoggableType();
     return builder.makeCall(
-      std::string("log-") + type.toString(), {make(type)}, none);
+      std::string("log-") + type.toString(), {make(type)}, Type::none);
   }
 
   Expression* makeMemoryHashLogging() {
-    auto* hash = builder.makeCall(std::string("hashMemory"), {}, i32);
-    return builder.makeCall(std::string("log-i32"), {hash}, none);
+    auto* hash = builder.makeCall(std::string("hashMemory"), {}, Type::i32);
+    return builder.makeCall(std::string("log-i32"), {hash}, Type::none);
   }
 
   // special getters
@@ -2850,7 +2857,7 @@ private:
     if (auto* block = target->dynCast<Block>()) {
       return block->type;
     } else if (target->is<Loop>()) {
-      return none;
+      return Type::none;
     }
     WASM_UNREACHABLE("unexpected expr type");
   }
diff --git a/src/tools/js-wrapper.h b/src/tools/js-wrapper.h
index a2d481f42..a787d4d2c 100644
--- a/src/tools/js-wrapper.h
+++ b/src/tools/js-wrapper.h
@@ -107,7 +107,7 @@ static std::string generateJSWrapper(Module& wasm) {
         ret += ", ";
       }
       ret += "0";
-      if (param == i64) {
+      if (param == Type::i64) {
         ret += ", 0";
       }
     }
diff --git a/src/tools/spec-wrapper.h b/src/tools/spec-wrapper.h
index f59291e55..2bad602f2 100644
--- a/src/tools/spec-wrapper.h
+++ b/src/tools/spec-wrapper.h
@@ -33,29 +33,29 @@ static std::string generateSpecWrapper(Module& wasm) {
     for (Type param : func->sig.params.expand()) {
       // zeros in arguments TODO more?
       switch (param) {
-        case i32:
+        case Type::i32:
           ret += "(i32.const 0)";
           break;
-        case i64:
+        case Type::i64:
           ret += "(i64.const 0)";
           break;
-        case f32:
+        case Type::f32:
           ret += "(f32.const 0)";
           break;
-        case f64:
+        case Type::f64:
           ret += "(f64.const 0)";
           break;
-        case v128:
+        case Type::v128:
           ret += "(v128.const i32x4 0 0 0 0)";
           break;
-        case funcref:
-        case anyref:
-        case nullref:
-        case exnref:
+        case Type::funcref:
+        case Type::anyref:
+        case Type::nullref:
+        case Type::exnref:
           ret += "(ref.null)";
           break;
-        case none:
-        case unreachable:
+        case Type::none:
+        case Type::unreachable:
           WASM_UNREACHABLE("unexpected type");
       }
       ret += " ";
diff --git a/src/tools/wasm-reduce.cpp b/src/tools/wasm-reduce.cpp
index 6adb1e174..5a05fc7d2 100644
--- a/src/tools/wasm-reduce.cpp
+++ b/src/tools/wasm-reduce.cpp
@@ -462,7 +462,7 @@ struct Reducer
 
   void visitExpression(Expression* curr) {
     // type-based reductions
-    if (curr->type == none) {
+    if (curr->type == Type::none) {
       if (tryToReduceCurrentToNop()) {
         return;
       }
@@ -471,14 +471,14 @@ struct Reducer
         return;
       }
     } else {
-      assert(curr->type == unreachable);
+      assert(curr->type == Type::unreachable);
       if (tryToReduceCurrentToUnreachable()) {
         return;
       }
     }
     // specific reductions
     if (auto* iff = curr->dynCast<If>()) {
-      if (iff->type == none) {
+      if (iff->type == Type::none) {
         // perhaps we need just the condition?
         if (tryToReplaceCurrent(builder->makeDrop(iff->condition))) {
           return;
@@ -556,7 +556,7 @@ struct Reducer
     }
     // Finally, try to replace with a child.
     for (auto* child : ChildIterator(curr)) {
-      if (child->type.isConcrete() && curr->type == none) {
+      if (child->type.isConcrete() && curr->type == Type::none) {
         if (tryToReplaceCurrent(builder->makeDrop(child))) {
           return;
         }
@@ -578,114 +578,114 @@ struct Reducer
         }
         Expression* fixed = nullptr;
         switch (curr->type) {
-          case i32: {
+          case Type::i32: {
             switch (child->type) {
-              case i32:
+              case Type::i32:
                 WASM_UNREACHABLE("invalid type");
-              case i64:
+              case Type::i64:
                 fixed = builder->makeUnary(WrapInt64, child);
                 break;
-              case f32:
+              case Type::f32:
                 fixed = builder->makeUnary(TruncSFloat32ToInt32, child);
                 break;
-              case f64:
+              case Type::f64:
                 fixed = builder->makeUnary(TruncSFloat64ToInt32, child);
                 break;
-              case v128:
-              case funcref:
-              case anyref:
-              case nullref:
-              case exnref:
+              case Type::v128:
+              case Type::funcref:
+              case Type::anyref:
+              case Type::nullref:
+              case Type::exnref:
                 continue; // not implemented yet
-              case none:
-              case unreachable:
+              case Type::none:
+              case Type::unreachable:
                 WASM_UNREACHABLE("unexpected type");
             }
             break;
           }
-          case i64: {
+          case Type::i64: {
             switch (child->type) {
-              case i32:
+              case Type::i32:
                 fixed = builder->makeUnary(ExtendSInt32, child);
                 break;
-              case i64:
+              case Type::i64:
                 WASM_UNREACHABLE("invalid type");
-              case f32:
+              case Type::f32:
                 fixed = builder->makeUnary(TruncSFloat32ToInt64, child);
                 break;
-              case f64:
+              case Type::f64:
                 fixed = builder->makeUnary(TruncSFloat64ToInt64, child);
                 break;
-              case v128:
-              case funcref:
-              case anyref:
-              case nullref:
-              case exnref:
+              case Type::v128:
+              case Type::funcref:
+              case Type::anyref:
+              case Type::nullref:
+              case Type::exnref:
                 continue; // not implemented yet
-              case none:
-              case unreachable:
+              case Type::none:
+              case Type::unreachable:
                 WASM_UNREACHABLE("unexpected type");
             }
             break;
           }
-          case f32: {
+          case Type::f32: {
             switch (child->type) {
-              case i32:
+              case Type::i32:
                 fixed = builder->makeUnary(ConvertSInt32ToFloat32, child);
                 break;
-              case i64:
+              case Type::i64:
                 fixed = builder->makeUnary(ConvertSInt64ToFloat32, child);
                 break;
-              case f32:
+              case Type::f32:
                 WASM_UNREACHABLE("unexpected type");
-              case f64:
+              case Type::f64:
                 fixed = builder->makeUnary(DemoteFloat64, child);
                 break;
-              case v128:
-              case funcref:
-              case anyref:
-              case nullref:
-              case exnref:
+              case Type::v128:
+              case Type::funcref:
+              case Type::anyref:
+              case Type::nullref:
+              case Type::exnref:
                 continue; // not implemented yet
-              case none:
-              case unreachable:
+              case Type::none:
+              case Type::unreachable:
                 WASM_UNREACHABLE("unexpected type");
             }
             break;
           }
-          case f64: {
+          case Type::f64: {
             switch (child->type) {
-              case i32:
+              case Type::i32:
                 fixed = builder->makeUnary(ConvertSInt32ToFloat64, child);
                 break;
-              case i64:
+              case Type::i64:
                 fixed = builder->makeUnary(ConvertSInt64ToFloat64, child);
                 break;
-              case f32:
+              case Type::f32:
                 fixed = builder->makeUnary(PromoteFloat32, child);
                 break;
-              case f64:
+              case Type::f64:
                 WASM_UNREACHABLE("unexpected type");
-              case v128:
-              case funcref:
-              case anyref:
-              case nullref:
-              case exnref:
+              case Type::v128:
+              case Type::funcref:
+              case Type::anyref:
+              case Type::nullref:
+              case Type::exnref:
                 continue; // not implemented yet
-              case none:
-              case unreachable:
+              case Type::none:
+              case Type::unreachable:
                 WASM_UNREACHABLE("unexpected type");
             }
             break;
           }
-          case v128:
-          case funcref:
-          case anyref:
-          case nullref:
-          case exnref:
+          case Type::v128:
+          case Type::funcref:
+          case Type::anyref:
+          case Type::nullref:
+          case Type::exnref:
             continue; // not implemented yet
-          case none:
-          case unreachable:
+          case Type::none:
+          case Type::unreachable:
             WASM_UNREACHABLE("unexpected type");
         }
         assert(fixed->type == curr->type);
@@ -879,7 +879,7 @@ struct Reducer
         auto funcSig = func->sig;
         auto* funcBody = func->body;
         for (auto* child : ChildIterator(func->body)) {
-          if (!(child->type.isConcrete() || child->type == none)) {
+          if (!(child->type.isConcrete() || child->type == Type::none)) {
             continue; // not something a function can return
           }
           // Try to replace the body with the child, fixing up the function
diff --git a/src/tools/wasm2js.cpp b/src/tools/wasm2js.cpp
index 7fa56c810..fabcf5522 100644
--- a/src/tools/wasm2js.cpp
+++ b/src/tools/wasm2js.cpp
@@ -565,7 +565,7 @@ Ref AssertionEmitter::emitAssertReturnFunc(Builder& wasmBuilder,
   Expression* actual = sexpBuilder.parseExpression(e[1]);
   Expression* body = nullptr;
   if (e.size() == 2) {
-    if (actual->type == none) {
+    if (actual->type == Type::none) {
       body = wasmBuilder.blockify(actual,
                                   wasmBuilder.makeConst(Literal(uint32_t(1))));
     } else {
@@ -576,25 +576,25 @@ Ref AssertionEmitter::emitAssertReturnFunc(Builder& wasmBuilder,
     Type resType = expected->type;
     actual->type = resType;
     switch (resType) {
-      case i32:
+      case Type::i32:
         body = wasmBuilder.makeBinary(EqInt32, actual, expected);
         break;
 
-      case i64:
+      case Type::i64:
         body = wasmBuilder.makeCall(
           "i64Equal",
           {actual,
-           wasmBuilder.makeCall(WASM_FETCH_HIGH_BITS, {}, i32),
+           wasmBuilder.makeCall(WASM_FETCH_HIGH_BITS, {}, Type::i32),
            expected},
-          i32);
+          Type::i32);
         break;
 
-      case f32: {
-        body = wasmBuilder.makeCall("f32Equal", {actual, expected}, i32);
+      case Type::f32: {
+        body = wasmBuilder.makeCall("f32Equal", {actual, expected}, Type::i32);
         break;
       }
-      case f64: {
-        body = wasmBuilder.makeCall("f64Equal", {actual, expected}, i32);
+      case Type::f64: {
+        body = wasmBuilder.makeCall("f64Equal", {actual, expected}, Type::i32);
         break;
       }
 
@@ -623,7 +623,7 @@ Ref AssertionEmitter::emitAssertReturnNanFunc(Builder& wasmBuilder,
                                               Name testFuncName,
                                               Name asmModule) {
   Expression* actual = sexpBuilder.parseExpression(e[1]);
-  Expression* body = wasmBuilder.makeCall("isNaN", {actual}, i32);
+  Expression* body = wasmBuilder.makeCall("isNaN", {actual}, Type::i32);
   std::unique_ptr<Function> testFunc(
     wasmBuilder.makeFunction(testFuncName,
                              std::vector<NameType>{},
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index f019d0792..6f8aa5744 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -905,37 +905,37 @@ inline S32LEB binaryType(Type type) {
   int ret = 0;
   switch (type) {
     // None only used for block signatures. TODO: Separate out?
-    case none:
+    case Type::none:
       ret = BinaryConsts::EncodedType::Empty;
       break;
-    case i32:
+    case Type::i32:
       ret = BinaryConsts::EncodedType::i32;
       break;
-    case i64:
+    case Type::i64:
       ret = BinaryConsts::EncodedType::i64;
       break;
-    case f32:
+    case Type::f32:
       ret = BinaryConsts::EncodedType::f32;
       break;
-    case f64:
+    case Type::f64:
       ret = BinaryConsts::EncodedType::f64;
       break;
-    case v128:
+    case Type::v128:
       ret = BinaryConsts::EncodedType::v128;
       break;
-    case funcref:
+    case Type::funcref:
       ret = BinaryConsts::EncodedType::funcref;
       break;
-    case anyref:
+    case Type::anyref:
       ret = BinaryConsts::EncodedType::anyref;
       break;
-    case nullref:
+    case Type::nullref:
       ret = BinaryConsts::EncodedType::nullref;
       break;
-    case exnref:
+    case Type::exnref:
       ret = BinaryConsts::EncodedType::exnref;
       break;
-    case unreachable:
+    case Type::unreachable:
       WASM_UNREACHABLE("unexpected type");
   }
   return S32LEB(ret);
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index 38009cb8a..a625d7e54 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -27,7 +27,7 @@ namespace wasm {
 struct NameType {
   Name name;
   Type type;
-  NameType() : name(nullptr), type(none) {}
+  NameType() : name(nullptr), type(Type::none) {}
   NameType(Name name, Type type) : name(name), type(type) {}
 };
 
@@ -774,32 +774,32 @@ public:
     Literal value;
     // TODO: reuse node conditionally when possible for literals
     switch (curr->type) {
-      case i32:
+      case Type::i32:
         value = Literal(int32_t(0));
         break;
-      case i64:
+      case Type::i64:
         value = Literal(int64_t(0));
         break;
-      case f32:
+      case Type::f32:
         value = Literal(float(0));
         break;
-      case f64:
+      case Type::f64:
         value = Literal(double(0));
         break;
-      case v128: {
+      case Type::v128: {
         std::array<uint8_t, 16> bytes;
         bytes.fill(0);
         value = Literal(bytes.data());
         break;
       }
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
         return ExpressionManipulator::refNull(curr);
-      case none:
+      case Type::none:
         return ExpressionManipulator::nop(curr);
-      case unreachable:
+      case Type::unreachable:
         return ExpressionManipulator::unreachable(curr);
     }
     return makeConst(value);
diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index f37a6edd6..a29af2216 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -1041,8 +1041,8 @@ public:
     if (std::isnan(val)) {
       trap("truncSFloat of nan");
     }
-    if (curr->type == i32) {
-      if (value.type == f32) {
+    if (curr->type == Type::i32) {
+      if (value.type == Type::f32) {
         if (!isInRangeI32TruncS(value.reinterpreti32())) {
           trap("i32.truncSFloat overflow");
         }
@@ -1053,7 +1053,7 @@ public:
       }
       return Literal(int32_t(val));
     } else {
-      if (value.type == f32) {
+      if (value.type == Type::f32) {
         if (!isInRangeI64TruncS(value.reinterpreti32())) {
           trap("i64.truncSFloat overflow");
         }
@@ -1071,8 +1071,8 @@ public:
     if (std::isnan(val)) {
       trap("truncUFloat of nan");
     }
-    if (curr->type == i32) {
-      if (value.type == f32) {
+    if (curr->type == Type::i32) {
+      if (value.type == Type::f32) {
         if (!isInRangeI32TruncU(value.reinterpreti32())) {
           trap("i32.truncUFloat overflow");
         }
@@ -1083,7 +1083,7 @@ public:
       }
       return Literal(uint32_t(val));
     } else {
-      if (value.type == f32) {
+      if (value.type == Type::f32) {
         if (!isInRangeI64TruncU(value.reinterpreti32())) {
           trap("i64.truncUFloat overflow");
         }
@@ -1135,7 +1135,7 @@ public:
     }
     Literal value = flow.value;
     NOTE_EVAL1(value);
-    return Literal(value.type == nullref);
+    return Literal(value.type == Type::nullref);
   }
   Flow visitRefFunc(RefFunc* curr) {
     NOTE_ENTER("RefFunc");
@@ -1198,7 +1198,7 @@ public:
     // customize load/store, or the sub-functions which they call
     virtual Literal load(Load* load, Address addr) {
       switch (load->type) {
-        case i32: {
+        case Type::i32: {
           switch (load->bytes) {
             case 1:
               return load->signed_ ? Literal((int32_t)load8s(addr))
@@ -1213,7 +1213,7 @@ public:
           }
           break;
         }
-        case i64: {
+        case Type::i64: {
           switch (load->bytes) {
             case 1:
               return load->signed_ ? Literal((int64_t)load8s(addr))
@@ -1231,25 +1231,25 @@ public:
           }
           break;
         }
-        case f32:
+        case Type::f32:
           return Literal(load32u(addr)).castToF32();
-        case f64:
+        case Type::f64:
           return Literal(load64u(addr)).castToF64();
-        case v128:
+        case Type::v128:
           return Literal(load128(addr).data());
-        case funcref:
-        case anyref:
-        case nullref:
-        case exnref:
-        case none:
-        case unreachable:
+        case Type::funcref:
+        case Type::anyref:
+        case Type::nullref:
+        case Type::exnref:
+        case Type::none:
+        case Type::unreachable:
           WASM_UNREACHABLE("unexpected type");
       }
       WASM_UNREACHABLE("invalid type");
     }
     virtual void store(Store* store, Address addr, Literal value) {
       switch (store->valueType) {
-        case i32: {
+        case Type::i32: {
           switch (store->bytes) {
             case 1:
               store8(addr, value.geti32());
@@ -1265,7 +1265,7 @@ public:
           }
           break;
         }
-        case i64: {
+        case Type::i64: {
           switch (store->bytes) {
             case 1:
               store8(addr, value.geti64());
@@ -1285,21 +1285,21 @@ public:
           break;
         }
         // write floats carefully, ensuring all bits reach memory
-        case f32:
+        case Type::f32:
           store32(addr, value.reinterpreti32());
           break;
-        case f64:
+        case Type::f64:
           store64(addr, value.reinterpreti64());
           break;
-        case v128:
+        case Type::v128:
           store128(addr, value.getv128());
           break;
-        case funcref:
-        case anyref:
-        case nullref:
-        case exnref:
-        case none:
-        case unreachable:
+        case Type::funcref:
+        case Type::anyref:
+        case Type::nullref:
+        case Type::exnref:
+        case Type::none:
+        case Type::unreachable:
           WASM_UNREACHABLE("unexpected type");
       }
     }
@@ -1790,7 +1790,7 @@ private:
     }
     Flow visitSIMDLoadSplat(SIMDLoad* curr) {
       Load load;
-      load.type = i32;
+      load.type = Type::i32;
       load.bytes = curr->getMemBytes();
       load.signed_ = false;
       load.offset = curr->offset;
@@ -1809,7 +1809,7 @@ private:
           splat = &Literal::splatI32x4;
           break;
         case LoadSplatVec64x2:
-          load.type = i64;
+          load.type = Type::i64;
           splat = &Literal::splatI64x2;
           break;
         default:
@@ -2125,7 +2125,7 @@ protected:
 
   template<class LS> Address getFinalAddress(LS* curr, Literal ptr) {
     Address memorySizeBytes = memorySize * Memory::kPageSize;
-    uint64_t addr = ptr.type == i32 ? ptr.geti32() : ptr.geti64();
+    uint64_t addr = ptr.type == Type::i32 ? ptr.geti32() : ptr.geti64();
     trapIfGt(curr->offset, memorySizeBytes, "offset > memory");
     trapIfGt(addr, memorySizeBytes - curr->offset, "final > memory");
     addr += curr->offset;
@@ -2136,7 +2136,7 @@ protected:
 
   Address getFinalAddress(Literal ptr, Index bytes) {
     Address memorySizeBytes = memorySize * Memory::kPageSize;
-    uint64_t addr = ptr.type == i32 ? ptr.geti32() : ptr.geti64();
+    uint64_t addr = ptr.type == Type::i32 ? ptr.geti32() : ptr.geti64();
     trapIfGt(addr, memorySizeBytes - bytes, "highest > memory");
     return addr;
   }
@@ -2150,7 +2150,7 @@ protected:
     checkLoadAddress(addr, bytes);
     Const ptr;
     ptr.value = Literal(int32_t(addr));
-    ptr.type = i32;
+    ptr.type = Type::i32;
     Load load;
     load.bytes = bytes;
     load.signed_ = true;
@@ -2164,7 +2164,7 @@ protected:
   void doAtomicStore(Address addr, Index bytes, Literal toStore) {
     Const ptr;
     ptr.value = Literal(int32_t(addr));
-    ptr.type = i32;
+    ptr.type = Type::i32;
     Const value;
     value.value = toStore;
     value.type = toStore.type;
diff --git a/src/wasm-s-parser.h b/src/wasm-s-parser.h
index 8cdcb88f4..e6b40eb08 100644
--- a/src/wasm-s-parser.h
+++ b/src/wasm-s-parser.h
@@ -161,7 +161,9 @@ private:
   Type
   stringToType(const char* str, bool allowError = false, bool prefix = false);
   Type stringToLaneType(const char* str);
-  bool isType(cashew::IString str) { return stringToType(str, true) != none; }
+  bool isType(cashew::IString str) {
+    return stringToType(str, true) != Type::none;
+  }
 
 public:
   Expression* parseExpression(Element* s) { return parseExpression(*s); }
diff --git a/src/wasm-stack.h b/src/wasm-stack.h
index 5f0bf12af..eeb675a3d 100644
--- a/src/wasm-stack.h
+++ b/src/wasm-stack.h
@@ -260,7 +260,8 @@ void BinaryenIRWriter<SubType>::visitPossibleBlockContents(Expression* curr) {
   for (auto* child : block->list) {
     visit(child);
   }
-  if (block->type == unreachable && block->list.back()->type != unreachable) {
+  if (block->type == Type::unreachable &&
+      block->list.back()->type != Type::unreachable) {
     // similar to in visitBlock, here we could skip emitting the block itself,
     // but must still end the 'block' (the contents, really) with an unreachable
     emitUnreachable();
@@ -283,7 +284,7 @@ void BinaryenIRWriter<SubType>::visitBlock(Block* curr) {
   };
 
   auto afterChildren = [this](Block* curr) {
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       // an unreachable block is one that cannot be exited. We cannot encode
       // this directly in wasm, where blocks must be none,i32,i64,f32,f64. Since
       // the block cannot be exited, we can emit an unreachable at the end, and
@@ -291,7 +292,7 @@ void BinaryenIRWriter<SubType>::visitBlock(Block* curr) {
       emitUnreachable();
     }
     emitScopeEnd(curr);
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       // and emit an unreachable *outside* the block too, so later things can
       // pop anything
       emitUnreachable();
@@ -331,7 +332,7 @@ void BinaryenIRWriter<SubType>::visitBlock(Block* curr) {
 
 template<typename SubType> void BinaryenIRWriter<SubType>::visitIf(If* curr) {
   visit(curr->condition);
-  if (curr->condition->type == unreachable) {
+  if (curr->condition->type == Type::unreachable) {
     // this if-else is unreachable because of the condition, i.e., the condition
     // does not exit. So don't emit the if (but do consume the condition)
     emitUnreachable();
@@ -346,7 +347,7 @@ template<typename SubType> void BinaryenIRWriter<SubType>::visitIf(If* curr) {
   }
 
   emitScopeEnd(curr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     // we already handled the case of the condition being unreachable.
     // otherwise, we may still be unreachable, if we are an if-else with both
     // sides unreachable. wasm does not allow this to be emitted directly, so we
@@ -361,13 +362,13 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitLoop(Loop* curr) {
   emit(curr);
   visitPossibleBlockContents(curr->body);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     // we emitted a loop without a return type, and the body might be block
     // contents, so ensure it is not consumed
     emitUnreachable();
   }
   emitScopeEnd(curr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     // we emitted a loop without a return type, so it must not be consumed
     emitUnreachable();
   }
@@ -382,7 +383,7 @@ void BinaryenIRWriter<SubType>::visitBreak(Break* curr) {
     visit(curr->condition);
   }
   emit(curr);
-  if (curr->condition && curr->type == unreachable) {
+  if (curr->condition && curr->type == Type::unreachable) {
     // a br_if is normally none or emits a value. if it is unreachable, then
     // either the condition or the value is unreachable, which is extremely
     // rare, and may require us to make the stack polymorphic (if the block we
@@ -436,7 +437,7 @@ void BinaryenIRWriter<SubType>::visitCall(Call* curr) {
   // the current value (here i32.eqz).
   //
   // The same applies for other expressions.
-  if (curr->type == unreachable && !curr->isReturn) {
+  if (curr->type == Type::unreachable && !curr->isReturn) {
     emitUnreachable();
     return;
   }
@@ -449,7 +450,7 @@ void BinaryenIRWriter<SubType>::visitCallIndirect(CallIndirect* curr) {
     visit(operand);
   }
   visit(curr->target);
-  if (curr->type == unreachable && !curr->isReturn) {
+  if (curr->type == Type::unreachable && !curr->isReturn) {
     emitUnreachable();
     return;
   }
@@ -464,7 +465,7 @@ void BinaryenIRWriter<SubType>::visitLocalGet(LocalGet* curr) {
 template<typename SubType>
 void BinaryenIRWriter<SubType>::visitLocalSet(LocalSet* curr) {
   visit(curr->value);
-  if (curr->isTee() && curr->type == unreachable) {
+  if (curr->isTee() && curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -485,7 +486,7 @@ void BinaryenIRWriter<SubType>::visitGlobalSet(GlobalSet* curr) {
 template<typename SubType>
 void BinaryenIRWriter<SubType>::visitLoad(Load* curr) {
   visit(curr->ptr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -503,7 +504,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitAtomicRMW(AtomicRMW* curr) {
   visit(curr->ptr);
   visit(curr->value);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -515,7 +516,7 @@ void BinaryenIRWriter<SubType>::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
   visit(curr->ptr);
   visit(curr->expected);
   visit(curr->replacement);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -527,7 +528,7 @@ void BinaryenIRWriter<SubType>::visitAtomicWait(AtomicWait* curr) {
   visit(curr->ptr);
   visit(curr->expected);
   visit(curr->timeout);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -538,7 +539,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitAtomicNotify(AtomicNotify* curr) {
   visit(curr->ptr);
   visit(curr->notifyCount);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -553,7 +554,7 @@ void BinaryenIRWriter<SubType>::visitAtomicFence(AtomicFence* curr) {
 template<typename SubType>
 void BinaryenIRWriter<SubType>::visitSIMDExtract(SIMDExtract* curr) {
   visit(curr->vec);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -564,7 +565,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitSIMDReplace(SIMDReplace* curr) {
   visit(curr->vec);
   visit(curr->value);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -575,7 +576,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitSIMDShuffle(SIMDShuffle* curr) {
   visit(curr->left);
   visit(curr->right);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -587,7 +588,7 @@ void BinaryenIRWriter<SubType>::visitSIMDTernary(SIMDTernary* curr) {
   visit(curr->a);
   visit(curr->b);
   visit(curr->c);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -598,7 +599,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitSIMDShift(SIMDShift* curr) {
   visit(curr->vec);
   visit(curr->shift);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -608,7 +609,7 @@ void BinaryenIRWriter<SubType>::visitSIMDShift(SIMDShift* curr) {
 template<typename SubType>
 void BinaryenIRWriter<SubType>::visitSIMDLoad(SIMDLoad* curr) {
   visit(curr->ptr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -652,7 +653,7 @@ void BinaryenIRWriter<SubType>::visitConst(Const* curr) {
 template<typename SubType>
 void BinaryenIRWriter<SubType>::visitUnary(Unary* curr) {
   visit(curr->value);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -663,7 +664,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitBinary(Binary* curr) {
   visit(curr->left);
   visit(curr->right);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -675,7 +676,7 @@ void BinaryenIRWriter<SubType>::visitSelect(Select* curr) {
   visit(curr->ifTrue);
   visit(curr->ifFalse);
   visit(curr->condition);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
     return;
   }
@@ -734,7 +735,7 @@ template<typename SubType> void BinaryenIRWriter<SubType>::visitTry(Try* curr) {
   emitCatch(curr);
   visitPossibleBlockContents(curr->catchBody);
   emitScopeEnd(curr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
   }
 }
@@ -757,7 +758,7 @@ template<typename SubType>
 void BinaryenIRWriter<SubType>::visitBrOnExn(BrOnExn* curr) {
   visit(curr->exnref);
   emit(curr);
-  if (curr->type == unreachable) {
+  if (curr->type == Type::unreachable) {
     emitUnreachable();
   }
 }
diff --git a/src/wasm-type.h b/src/wasm-type.h
index 668ac3e4d..18c429e95 100644
--- a/src/wasm-type.h
+++ b/src/wasm-type.h
@@ -148,18 +148,6 @@ std::ostream& operator<<(std::ostream& os, ParamType t);
 std::ostream& operator<<(std::ostream& os, ResultType t);
 std::ostream& operator<<(std::ostream& os, Signature t);
 
-constexpr Type none = Type::none;
-constexpr Type i32 = Type::i32;
-constexpr Type i64 = Type::i64;
-constexpr Type f32 = Type::f32;
-constexpr Type f64 = Type::f64;
-constexpr Type v128 = Type::v128;
-constexpr Type funcref = Type::funcref;
-constexpr Type anyref = Type::anyref;
-constexpr Type nullref = Type::nullref;
-constexpr Type exnref = Type::exnref;
-constexpr Type unreachable = Type::unreachable;
-
 } // namespace wasm
 
 template<> class std::hash<wasm::Signature> {
diff --git a/src/wasm.h b/src/wasm.h
index c4dbd2f3f..77bf75545 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -543,7 +543,7 @@ public:
   Id _id;
 
   // the type of the expression: its *output*, not necessarily its input(s)
-  Type type = none;
+  Type type = Type::none;
 
   Expression(Id id) : _id(id) {}
 
@@ -655,7 +655,7 @@ public:
 class Break : public SpecificExpression<Expression::BreakId> {
 public:
   Break() : value(nullptr), condition(nullptr) {}
-  Break(MixedArena& allocator) : Break() { type = unreachable; }
+  Break(MixedArena& allocator) : Break() { type = Type::unreachable; }
 
   Name name;
   Expression* value;
@@ -666,7 +666,9 @@ public:
 
 class Switch : public SpecificExpression<Expression::SwitchId> {
 public:
-  Switch(MixedArena& allocator) : targets(allocator) { type = unreachable; }
+  Switch(MixedArena& allocator) : targets(allocator) {
+    type = Type::unreachable;
+  }
 
   ArenaVector<Name> targets;
   Name default_;
@@ -1028,7 +1030,7 @@ public:
 
 class Return : public SpecificExpression<Expression::ReturnId> {
 public:
-  Return() { type = unreachable; }
+  Return() { type = Type::unreachable; }
   Return(MixedArena& allocator) : Return() {}
 
   Expression* value = nullptr;
@@ -1047,7 +1049,7 @@ public:
 
 class Unreachable : public SpecificExpression<Expression::UnreachableId> {
 public:
-  Unreachable() { type = unreachable; }
+  Unreachable() { type = Type::unreachable; }
   Unreachable(MixedArena& allocator) : Unreachable() {}
 };
 
@@ -1134,7 +1136,7 @@ public:
 
 class BrOnExn : public SpecificExpression<Expression::BrOnExnId> {
 public:
-  BrOnExn() { type = unreachable; }
+  BrOnExn() { type = Type::unreachable; }
   BrOnExn(MixedArena& allocator) : BrOnExn() {}
 
   Name name;
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index ba5a8d3dd..4b748a5af 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -1048,25 +1048,25 @@ Type WasmBinaryBuilder::getType() {
   switch (type) {
     // None only used for block signatures. TODO: Separate out?
     case BinaryConsts::EncodedType::Empty:
-      return none;
+      return Type::none;
     case BinaryConsts::EncodedType::i32:
-      return i32;
+      return Type::i32;
     case BinaryConsts::EncodedType::i64:
-      return i64;
+      return Type::i64;
     case BinaryConsts::EncodedType::f32:
-      return f32;
+      return Type::f32;
     case BinaryConsts::EncodedType::f64:
-      return f64;
+      return Type::f64;
     case BinaryConsts::EncodedType::v128:
-      return v128;
+      return Type::v128;
     case BinaryConsts::EncodedType::funcref:
-      return funcref;
+      return Type::funcref;
     case BinaryConsts::EncodedType::anyref:
-      return anyref;
+      return Type::anyref;
     case BinaryConsts::EncodedType::nullref:
-      return nullref;
+      return Type::nullref;
     case BinaryConsts::EncodedType::exnref:
-      return exnref;
+      return Type::exnref;
     default:
       throwError("invalid wasm type: " + std::to_string(type));
   }
@@ -1648,7 +1648,7 @@ void WasmBinaryBuilder::processExpressions() {
       return;
     }
     expressionStack.push_back(curr);
-    if (curr->type == unreachable) {
+    if (curr->type == Type::unreachable) {
       // once we see something unreachable, we don't want to add anything else
       // to the stack, as it could be stacky code that is non-representable in
       // our AST. but we do need to skip it
@@ -1730,7 +1730,7 @@ Expression* WasmBinaryBuilder::popExpression() {
 
 Expression* WasmBinaryBuilder::popNonVoidExpression() {
   auto* ret = popExpression();
-  if (ret->type != none) {
+  if (ret->type != Type::none) {
     return ret;
   }
   // we found a void, so this is stacky code that we must handle carefully
@@ -1741,7 +1741,7 @@ Expression* WasmBinaryBuilder::popNonVoidExpression() {
   while (1) {
     auto* curr = popExpression();
     expressions.push_back(curr);
-    if (curr->type != none) {
+    if (curr->type != Type::none) {
       break;
     }
   }
@@ -1757,7 +1757,7 @@ Expression* WasmBinaryBuilder::popNonVoidExpression() {
     block->list[0] = builder.makeLocalSet(local, block->list[0]);
     block->list.push_back(builder.makeLocalGet(local, type));
   } else {
-    assert(type == unreachable);
+    assert(type == Type::unreachable);
     // nothing to do here - unreachable anyhow
   }
   block->finalize();
@@ -2318,7 +2318,7 @@ void WasmBinaryBuilder::pushBlockElements(Block* curr,
   }
   expressionStack.resize(start);
   // if we have a consumable item and need it, use it
-  if (consumable != NONE && curr->list.back()->type == none) {
+  if (consumable != NONE && curr->list.back()->type == Type::none) {
     requireFunctionContext(
       "need an extra var in a non-function context, invalid wasm");
     Builder builder(wasm);
@@ -2338,7 +2338,7 @@ void WasmBinaryBuilder::visitBlock(Block* curr) {
   while (1) {
     curr->type = getType();
     curr->name = getNextLabel();
-    breakStack.push_back({curr->name, curr->type != none});
+    breakStack.push_back({curr->name, curr->type != Type::none});
     stack.push_back(curr);
     if (more() && input[pos] == BinaryConsts::Block) {
       // a recursion
@@ -2386,12 +2386,13 @@ void WasmBinaryBuilder::visitBlock(Block* curr) {
 Expression* WasmBinaryBuilder::getBlockOrSingleton(Type type,
                                                    unsigned numPops) {
   Name label = getNextLabel();
-  breakStack.push_back({label, type != none && type != unreachable});
+  breakStack.push_back(
+    {label, type != Type::none && type != Type::unreachable});
   auto start = expressionStack.size();
 
   Builder builder(wasm);
   for (unsigned i = 0; i < numPops; i++) {
-    auto* pop = builder.makePop(exnref);
+    auto* pop = builder.makePop(Type::exnref);
     expressionStack.push_back(pop);
   }
 
@@ -2615,82 +2616,82 @@ bool WasmBinaryBuilder::maybeVisitLoad(Expression*& out,
       case BinaryConsts::I32LoadMem8S:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i32;
+        curr->type = Type::i32;
         curr->signed_ = true;
         break;
       case BinaryConsts::I32LoadMem8U:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i32;
+        curr->type = Type::i32;
         curr->signed_ = false;
         break;
       case BinaryConsts::I32LoadMem16S:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i32;
+        curr->type = Type::i32;
         curr->signed_ = true;
         break;
       case BinaryConsts::I32LoadMem16U:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i32;
+        curr->type = Type::i32;
         curr->signed_ = false;
         break;
       case BinaryConsts::I32LoadMem:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = i32;
+        curr->type = Type::i32;
         break;
       case BinaryConsts::I64LoadMem8S:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = true;
         break;
       case BinaryConsts::I64LoadMem8U:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = false;
         break;
       case BinaryConsts::I64LoadMem16S:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = true;
         break;
       case BinaryConsts::I64LoadMem16U:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = false;
         break;
       case BinaryConsts::I64LoadMem32S:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = true;
         break;
       case BinaryConsts::I64LoadMem32U:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = i64;
+        curr->type = Type::i64;
         curr->signed_ = false;
         break;
       case BinaryConsts::I64LoadMem:
         curr = allocator.alloc<Load>();
         curr->bytes = 8;
-        curr->type = i64;
+        curr->type = Type::i64;
         break;
       case BinaryConsts::F32LoadMem:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = f32;
+        curr->type = Type::f32;
         break;
       case BinaryConsts::F64LoadMem:
         curr = allocator.alloc<Load>();
         curr->bytes = 8;
-        curr->type = f64;
+        curr->type = Type::f64;
         break;
       default:
         return false;
@@ -2701,37 +2702,37 @@ bool WasmBinaryBuilder::maybeVisitLoad(Expression*& out,
       case BinaryConsts::I32AtomicLoad8U:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i32;
+        curr->type = Type::i32;
         break;
       case BinaryConsts::I32AtomicLoad16U:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i32;
+        curr->type = Type::i32;
         break;
       case BinaryConsts::I32AtomicLoad:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = i32;
+        curr->type = Type::i32;
         break;
       case BinaryConsts::I64AtomicLoad8U:
         curr = allocator.alloc<Load>();
         curr->bytes = 1;
-        curr->type = i64;
+        curr->type = Type::i64;
         break;
       case BinaryConsts::I64AtomicLoad16U:
         curr = allocator.alloc<Load>();
         curr->bytes = 2;
-        curr->type = i64;
+        curr->type = Type::i64;
         break;
       case BinaryConsts::I64AtomicLoad32U:
         curr = allocator.alloc<Load>();
         curr->bytes = 4;
-        curr->type = i64;
+        curr->type = Type::i64;
         break;
       case BinaryConsts::I64AtomicLoad:
         curr = allocator.alloc<Load>();
         curr->bytes = 8;
-        curr->type = i64;
+        curr->type = Type::i64;
         break;
       default:
         return false;
@@ -2757,47 +2758,47 @@ bool WasmBinaryBuilder::maybeVisitStore(Expression*& out,
       case BinaryConsts::I32StoreMem8:
         curr = allocator.alloc<Store>();
         curr->bytes = 1;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I32StoreMem16:
         curr = allocator.alloc<Store>();
         curr->bytes = 2;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I32StoreMem:
         curr = allocator.alloc<Store>();
         curr->bytes = 4;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I64StoreMem8:
         curr = allocator.alloc<Store>();
         curr->bytes = 1;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64StoreMem16:
         curr = allocator.alloc<Store>();
         curr->bytes = 2;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64StoreMem32:
         curr = allocator.alloc<Store>();
         curr->bytes = 4;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64StoreMem:
         curr = allocator.alloc<Store>();
         curr->bytes = 8;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::F32StoreMem:
         curr = allocator.alloc<Store>();
         curr->bytes = 4;
-        curr->valueType = f32;
+        curr->valueType = Type::f32;
         break;
       case BinaryConsts::F64StoreMem:
         curr = allocator.alloc<Store>();
         curr->bytes = 8;
-        curr->valueType = f64;
+        curr->valueType = Type::f64;
         break;
       default:
         return false;
@@ -2807,37 +2808,37 @@ bool WasmBinaryBuilder::maybeVisitStore(Expression*& out,
       case BinaryConsts::I32AtomicStore8:
         curr = allocator.alloc<Store>();
         curr->bytes = 1;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I32AtomicStore16:
         curr = allocator.alloc<Store>();
         curr->bytes = 2;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I32AtomicStore:
         curr = allocator.alloc<Store>();
         curr->bytes = 4;
-        curr->valueType = i32;
+        curr->valueType = Type::i32;
         break;
       case BinaryConsts::I64AtomicStore8:
         curr = allocator.alloc<Store>();
         curr->bytes = 1;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64AtomicStore16:
         curr = allocator.alloc<Store>();
         curr->bytes = 2;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64AtomicStore32:
         curr = allocator.alloc<Store>();
         curr->bytes = 4;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       case BinaryConsts::I64AtomicStore:
         curr = allocator.alloc<Store>();
         curr->bytes = 8;
-        curr->valueType = i64;
+        curr->valueType = Type::i64;
         break;
       default:
         return false;
@@ -2870,25 +2871,25 @@ bool WasmBinaryBuilder::maybeVisitAtomicRMW(Expression*& out, uint8_t code) {
   // Handle the cases for all the valid types for a particular opcode
 #define SET_FOR_OP(Op)                                                         \
   case BinaryConsts::I32AtomicRMW##Op:                                         \
-    SET(Op, i32, 4);                                                           \
+    SET(Op, Type::i32, 4);                                                     \
     break;                                                                     \
   case BinaryConsts::I32AtomicRMW##Op##8U:                                     \
-    SET(Op, i32, 1);                                                           \
+    SET(Op, Type::i32, 1);                                                     \
     break;                                                                     \
   case BinaryConsts::I32AtomicRMW##Op##16U:                                    \
-    SET(Op, i32, 2);                                                           \
+    SET(Op, Type::i32, 2);                                                     \
     break;                                                                     \
   case BinaryConsts::I64AtomicRMW##Op:                                         \
-    SET(Op, i64, 8);                                                           \
+    SET(Op, Type::i64, 8);                                                     \
     break;                                                                     \
   case BinaryConsts::I64AtomicRMW##Op##8U:                                     \
-    SET(Op, i64, 1);                                                           \
+    SET(Op, Type::i64, 1);                                                     \
     break;                                                                     \
   case BinaryConsts::I64AtomicRMW##Op##16U:                                    \
-    SET(Op, i64, 2);                                                           \
+    SET(Op, Type::i64, 2);                                                     \
     break;                                                                     \
   case BinaryConsts::I64AtomicRMW##Op##32U:                                    \
-    SET(Op, i64, 4);                                                           \
+    SET(Op, Type::i64, 4);                                                     \
     break;
 
   switch (code) {
@@ -2932,25 +2933,25 @@ bool WasmBinaryBuilder::maybeVisitAtomicCmpxchg(Expression*& out,
 
   switch (code) {
     case BinaryConsts::I32AtomicCmpxchg:
-      SET(i32, 4);
+      SET(Type::i32, 4);
       break;
     case BinaryConsts::I64AtomicCmpxchg:
-      SET(i64, 8);
+      SET(Type::i64, 8);
       break;
     case BinaryConsts::I32AtomicCmpxchg8U:
-      SET(i32, 1);
+      SET(Type::i32, 1);
       break;
     case BinaryConsts::I32AtomicCmpxchg16U:
-      SET(i32, 2);
+      SET(Type::i32, 2);
       break;
     case BinaryConsts::I64AtomicCmpxchg8U:
-      SET(i64, 1);
+      SET(Type::i64, 1);
       break;
     case BinaryConsts::I64AtomicCmpxchg16U:
-      SET(i64, 2);
+      SET(Type::i64, 2);
       break;
     case BinaryConsts::I64AtomicCmpxchg32U:
-      SET(i64, 4);
+      SET(Type::i64, 4);
       break;
     default:
       WASM_UNREACHABLE("unexpected opcode");
@@ -2979,15 +2980,15 @@ bool WasmBinaryBuilder::maybeVisitAtomicWait(Expression*& out, uint8_t code) {
 
   switch (code) {
     case BinaryConsts::I32AtomicWait:
-      curr->expectedType = i32;
+      curr->expectedType = Type::i32;
       break;
     case BinaryConsts::I64AtomicWait:
-      curr->expectedType = i64;
+      curr->expectedType = Type::i64;
       break;
     default:
       WASM_UNREACHABLE("unexpected opcode");
   }
-  curr->type = i32;
+  curr->type = Type::i32;
   BYN_TRACE("zz node: AtomicWait\n");
   curr->timeout = popNonVoidExpression();
   curr->expected = popNonVoidExpression();
@@ -3009,7 +3010,7 @@ bool WasmBinaryBuilder::maybeVisitAtomicNotify(Expression*& out, uint8_t code) {
   auto* curr = allocator.alloc<AtomicNotify>();
   BYN_TRACE("zz node: AtomicNotify\n");
 
-  curr->type = i32;
+  curr->type = Type::i32;
   curr->notifyCount = popNonVoidExpression();
   curr->ptr = popNonVoidExpression();
   Address readAlign;
@@ -4067,7 +4068,7 @@ bool WasmBinaryBuilder::maybeVisitSIMDStore(Expression*& out, uint32_t code) {
   }
   auto* curr = allocator.alloc<Store>();
   curr->bytes = 16;
-  curr->valueType = v128;
+  curr->valueType = Type::v128;
   readMemoryAccess(curr->align, curr->offset);
   curr->isAtomic = false;
   curr->value = popNonVoidExpression();
@@ -4285,7 +4286,7 @@ bool WasmBinaryBuilder::maybeVisitSIMDShift(Expression*& out, uint32_t code) {
 bool WasmBinaryBuilder::maybeVisitSIMDLoad(Expression*& out, uint32_t code) {
   if (code == BinaryConsts::V128Load) {
     auto* curr = allocator.alloc<Load>();
-    curr->type = v128;
+    curr->type = Type::v128;
     curr->bytes = 16;
     readMemoryAccess(curr->align, curr->offset);
     curr->isAtomic = false;
diff --git a/src/wasm/wasm-emscripten.cpp b/src/wasm/wasm-emscripten.cpp
index 3d65f9de2..8357983b2 100644
--- a/src/wasm/wasm-emscripten.cpp
+++ b/src/wasm/wasm-emscripten.cpp
@@ -89,13 +89,13 @@ Expression* EmscriptenGlueGenerator::generateLoadStackPointer() {
       /* offset =*/stackPointerOffset,
       /* align  =*/4,
       /* ptr    =*/builder.makeConst(Literal(0)),
-      /* type   =*/i32);
+      /* type   =*/Type::i32);
   }
   Global* stackPointer = getStackPointerGlobal();
   if (!stackPointer) {
     Fatal() << "stack pointer global not found";
   }
-  return builder.makeGlobalGet(stackPointer->name, i32);
+  return builder.makeGlobalGet(stackPointer->name, Type::i32);
 }
 
 inline Expression* stackBoundsCheck(Builder& builder,
@@ -111,7 +111,7 @@ inline Expression* stackBoundsCheck(Builder& builder,
   // Otherwise, just trap.
   Expression* handler;
   if (handlerName.is()) {
-    handler = builder.makeCall(handlerName, {}, none);
+    handler = builder.makeCall(handlerName, {}, Type::none);
   } else {
     handler = builder.makeUnreachable();
   }
@@ -139,7 +139,7 @@ EmscriptenGlueGenerator::generateStoreStackPointer(Function* func,
       /* align  =*/4,
       /* ptr    =*/builder.makeConst(Literal(0)),
       /* value  =*/value,
-      /* type   =*/i32);
+      /* type   =*/Type::i32);
   }
   Global* stackPointer = getStackPointerGlobal();
   if (!stackPointer) {
@@ -160,7 +160,7 @@ void EmscriptenGlueGenerator::generateStackSaveFunction() {
   BYN_TRACE("generateStackSaveFunction\n");
   std::vector<NameType> params{};
   Function* function =
-    builder.makeFunction(STACK_SAVE, std::move(params), i32, {});
+    builder.makeFunction(STACK_SAVE, std::move(params), Type::i32, {});
 
   function->body = generateLoadStackPointer();
 
@@ -169,24 +169,24 @@ void EmscriptenGlueGenerator::generateStackSaveFunction() {
 
 void EmscriptenGlueGenerator::generateStackAllocFunction() {
   BYN_TRACE("generateStackAllocFunction\n");
-  std::vector<NameType> params{{"0", i32}};
-  Function* function =
-    builder.makeFunction(STACK_ALLOC, std::move(params), i32, {{"1", i32}});
+  std::vector<NameType> params{{"0", Type::i32}};
+  Function* function = builder.makeFunction(
+    STACK_ALLOC, std::move(params), Type::i32, {{"1", Type::i32}});
   Expression* loadStack = generateLoadStackPointer();
-  LocalGet* getSizeArg = builder.makeLocalGet(0, i32);
+  LocalGet* getSizeArg = builder.makeLocalGet(0, Type::i32);
   Binary* sub = builder.makeBinary(SubInt32, loadStack, getSizeArg);
   const static uint32_t bitAlignment = 16;
   const static uint32_t bitMask = bitAlignment - 1;
   Const* subConst = builder.makeConst(Literal(~bitMask));
   Binary* maskedSub = builder.makeBinary(AndInt32, sub, subConst);
-  LocalSet* teeStackLocal = builder.makeLocalTee(1, maskedSub, i32);
+  LocalSet* teeStackLocal = builder.makeLocalTee(1, maskedSub, Type::i32);
   Expression* storeStack = generateStoreStackPointer(function, teeStackLocal);
 
   Block* block = builder.makeBlock();
   block->list.push_back(storeStack);
-  LocalGet* getStackLocal2 = builder.makeLocalGet(1, i32);
+  LocalGet* getStackLocal2 = builder.makeLocalGet(1, Type::i32);
   block->list.push_back(getStackLocal2);
-  block->type = i32;
+  block->type = Type::i32;
   function->body = block;
 
   addExportedFunction(wasm, function);
@@ -194,10 +194,10 @@ void EmscriptenGlueGenerator::generateStackAllocFunction() {
 
 void EmscriptenGlueGenerator::generateStackRestoreFunction() {
   BYN_TRACE("generateStackRestoreFunction\n");
-  std::vector<NameType> params{{"0", i32}};
+  std::vector<NameType> params{{"0", Type::i32}};
   Function* function =
-    builder.makeFunction(STACK_RESTORE, std::move(params), none, {});
-  LocalGet* getArg = builder.makeLocalGet(0, i32);
+    builder.makeFunction(STACK_RESTORE, std::move(params), Type::none, {});
+  LocalGet* getArg = builder.makeLocalGet(0, Type::i32);
   Expression* store = generateStoreStackPointer(function, getArg);
 
   function->body = store;
@@ -264,15 +264,15 @@ Function* EmscriptenGlueGenerator::generateAssignGOTEntriesFunction() {
     return nullptr;
   }
 
-  Function* assignFunc =
-    builder.makeFunction(ASSIGN_GOT_ENTIRES, std::vector<NameType>{}, none, {});
+  Function* assignFunc = builder.makeFunction(
+    ASSIGN_GOT_ENTIRES, std::vector<NameType>{}, Type::none, {});
   Block* block = builder.makeBlock();
   assignFunc->body = block;
 
   for (Global* g : gotMemEntries) {
     Name getter(std::string("g$") + g->base.c_str());
     ensureFunctionImport(&wasm, getter, Signature(Type::none, Type::i32));
-    Expression* call = builder.makeCall(getter, {}, i32);
+    Expression* call = builder.makeCall(getter, {}, Type::i32);
     GlobalSet* globalSet = builder.makeGlobalSet(g->name, call);
     block->list.push_back(globalSet);
   }
@@ -298,7 +298,7 @@ Function* EmscriptenGlueGenerator::generateAssignGOTEntriesFunction() {
       (std::string("fp$") + g->base.c_str() + std::string("$") + getSig(f))
         .c_str());
     ensureFunctionImport(&wasm, getter, Signature(Type::none, Type::i32));
-    Expression* call = builder.makeCall(getter, {}, i32);
+    Expression* call = builder.makeCall(getter, {}, Type::i32);
     GlobalSet* globalSet = builder.makeGlobalSet(g->name, call);
     block->list.push_back(globalSet);
   }
@@ -322,13 +322,13 @@ Function* EmscriptenGlueGenerator::generateAssignGOTEntriesFunction() {
 void EmscriptenGlueGenerator::generatePostInstantiateFunction() {
   BYN_TRACE("generatePostInstantiateFunction\n");
   Builder builder(wasm);
-  Function* post_instantiate =
-    builder.makeFunction(POST_INSTANTIATE, std::vector<NameType>{}, none, {});
+  Function* post_instantiate = builder.makeFunction(
+    POST_INSTANTIATE, std::vector<NameType>{}, Type::none, {});
   wasm.addFunction(post_instantiate);
 
   if (Function* F = generateAssignGOTEntriesFunction()) {
     // call __assign_got_enties from post_instantiate
-    Expression* call = builder.makeCall(F->name, {}, none);
+    Expression* call = builder.makeCall(F->name, {}, Type::none);
     post_instantiate->body = builder.blockify(post_instantiate->body, call);
   }
 
@@ -336,7 +336,7 @@ void EmscriptenGlueGenerator::generatePostInstantiateFunction() {
   // expected by emscripten.
   // TODO(sbc): Unify these
   if (auto* e = wasm.getExportOrNull(WASM_CALL_CTORS)) {
-    Expression* call = builder.makeCall(e->value, {}, none);
+    Expression* call = builder.makeCall(e->value, {}, Type::none);
     post_instantiate->body = builder.blockify(post_instantiate->body, call);
     wasm.removeExport(WASM_CALL_CTORS);
   }
@@ -350,11 +350,11 @@ void EmscriptenGlueGenerator::generatePostInstantiateFunction() {
 
 Function* EmscriptenGlueGenerator::generateMemoryGrowthFunction() {
   Name name(GROW_WASM_MEMORY);
-  std::vector<NameType> params{{NEW_SIZE, i32}};
+  std::vector<NameType> params{{NEW_SIZE, Type::i32}};
   Function* growFunction =
-    builder.makeFunction(name, std::move(params), i32, {});
+    builder.makeFunction(name, std::move(params), Type::i32, {});
   growFunction->body =
-    builder.makeHost(MemoryGrow, Name(), {builder.makeLocalGet(0, i32)});
+    builder.makeHost(MemoryGrow, Name(), {builder.makeLocalGet(0, Type::i32)});
 
   addExportedFunction(wasm, growFunction);
 
@@ -384,14 +384,14 @@ void EmscriptenGlueGenerator::generateDynCallThunk(Signature sig) {
     return; // module already contains this dyncall
   }
   std::vector<NameType> params;
-  params.emplace_back("fptr", i32); // function pointer param
+  params.emplace_back("fptr", Type::i32); // function pointer param
   int p = 0;
   const std::vector<Type>& paramTypes = sig.params.expand();
   for (const auto& ty : paramTypes) {
     params.emplace_back(std::to_string(p++), ty);
   }
   Function* f = builder.makeFunction(name, std::move(params), sig.results, {});
-  Expression* fptr = builder.makeLocalGet(0, i32);
+  Expression* fptr = builder.makeLocalGet(0, Type::i32);
   std::vector<Expression*> args;
   for (unsigned i = 0; i < paramTypes.size(); ++i) {
     args.push_back(builder.makeLocalGet(i + 1, paramTypes[i]));
@@ -423,7 +423,7 @@ struct RemoveStackPointer : public PostWalker<RemoveStackPointer> {
       if (!builder) {
         builder = make_unique<Builder>(*getModule());
       }
-      replaceCurrent(builder->makeCall(STACK_SAVE, {}, i32));
+      replaceCurrent(builder->makeCall(STACK_SAVE, {}, Type::i32));
     }
   }
 
@@ -433,7 +433,8 @@ struct RemoveStackPointer : public PostWalker<RemoveStackPointer> {
       if (!builder) {
         builder = make_unique<Builder>(*getModule());
       }
-      replaceCurrent(builder->makeCall(STACK_RESTORE, {curr->value}, none));
+      replaceCurrent(
+        builder->makeCall(STACK_RESTORE, {curr->value}, Type::none));
     }
   }
 
@@ -548,7 +549,7 @@ void EmscriptenGlueGenerator::enforceStackLimit() {
 void EmscriptenGlueGenerator::generateSetStackLimitFunction() {
   Function* function =
     builder.makeFunction(SET_STACK_LIMIT, Signature(Type::i32, Type::none), {});
-  LocalGet* getArg = builder.makeLocalGet(0, i32);
+  LocalGet* getArg = builder.makeLocalGet(0, Type::i32);
   Expression* store = builder.makeGlobalSet(STACK_LIMIT, getArg);
   function->body = store;
   addExportedFunction(wasm, function);
@@ -1227,7 +1228,7 @@ std::string EmscriptenGlueGenerator::generateEmscriptenMetadata(
     for (const auto& ex : wasm.exports) {
       if (ex->kind == ExternalKind::Global) {
         const Global* g = wasm.getGlobal(ex->value);
-        assert(g->type == i32);
+        assert(g->type == Type::i32);
         Const* init = g->init->cast<Const>();
         uint32_t addr = init->value.geti32();
         meta << nextElement() << '"' << ex->name.str << "\" : \"" << addr
@@ -1313,10 +1314,11 @@ void EmscriptenGlueGenerator::exportWasiStart() {
   }
   BYN_TRACE("exportWasiStart\n");
   Builder builder(wasm);
-  auto* body = builder.makeDrop(builder.makeCall(
-    main,
-    {LiteralUtils::makeZero(i32, wasm), LiteralUtils::makeZero(i32, wasm)},
-    i32));
+  auto* body =
+    builder.makeDrop(builder.makeCall(main,
+                                      {LiteralUtils::makeZero(Type::i32, wasm),
+                                       LiteralUtils::makeZero(Type::i32, wasm)},
+                                      Type::i32));
   auto* func =
     builder.makeFunction(_start, Signature(Type::none, Type::none), {}, body);
   wasm.addFunction(func);
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 7ff946200..573df9dfa 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -833,64 +833,64 @@ Type SExpressionWasmBuilder::stringToType(const char* str,
                                           bool prefix) {
   if (str[0] == 'i') {
     if (str[1] == '3' && str[2] == '2' && (prefix || str[3] == 0)) {
-      return i32;
+      return Type::i32;
     }
     if (str[1] == '6' && str[2] == '4' && (prefix || str[3] == 0)) {
-      return i64;
+      return Type::i64;
     }
   }
   if (str[0] == 'f') {
     if (str[1] == '3' && str[2] == '2' && (prefix || str[3] == 0)) {
-      return f32;
+      return Type::f32;
     }
     if (str[1] == '6' && str[2] == '4' && (prefix || str[3] == 0)) {
-      return f64;
+      return Type::f64;
     }
   }
   if (str[0] == 'v') {
     if (str[1] == '1' && str[2] == '2' && str[3] == '8' &&
         (prefix || str[4] == 0)) {
-      return v128;
+      return Type::v128;
     }
   }
   if (strncmp(str, "funcref", 7) == 0 && (prefix || str[7] == 0)) {
-    return funcref;
+    return Type::funcref;
   }
   if (strncmp(str, "anyref", 6) == 0 && (prefix || str[6] == 0)) {
-    return anyref;
+    return Type::anyref;
   }
   if (strncmp(str, "nullref", 7) == 0 && (prefix || str[7] == 0)) {
-    return nullref;
+    return Type::nullref;
   }
   if (strncmp(str, "exnref", 6) == 0 && (prefix || str[6] == 0)) {
-    return exnref;
+    return Type::exnref;
   }
   if (allowError) {
-    return none;
+    return Type::none;
   }
   throw ParseException(std::string("invalid wasm type: ") + str);
 }
 
 Type SExpressionWasmBuilder::stringToLaneType(const char* str) {
   if (strcmp(str, "i8x16") == 0) {
-    return i32;
+    return Type::i32;
   }
   if (strcmp(str, "i16x8") == 0) {
-    return i32;
+    return Type::i32;
   }
   if (strcmp(str, "i32x4") == 0) {
-    return i32;
+    return Type::i32;
   }
   if (strcmp(str, "i64x2") == 0) {
-    return i64;
+    return Type::i64;
   }
   if (strcmp(str, "f32x4") == 0) {
-    return f32;
+    return Type::f32;
   }
   if (strcmp(str, "f64x2") == 0) {
-    return f64;
+    return Type::f64;
   }
-  return none;
+  return Type::none;
 }
 
 Function::DebugLocation
@@ -1067,7 +1067,7 @@ Expression* SExpressionWasmBuilder::makeBlock(Element& s) {
     if (i < s.size() && s[i]->isStr()) {
       // could be a name or a type
       if (s[i]->dollared() ||
-          stringToType(s[i]->str(), true /* allowError */) == none) {
+          stringToType(s[i]->str(), true /* allowError */) == Type::none) {
         sName = s[i++]->str();
       } else {
         sName = "block";
@@ -1152,7 +1152,7 @@ static Literal makeLanes(Element& s, MixedArena& allocator, Type lane_t) {
 }
 
 Expression* SExpressionWasmBuilder::makeConst(Element& s, Type type) {
-  if (type != v128) {
+  if (type != Type::v128) {
     auto ret = parseConst(s[1]->str(), type, allocator);
     if (!ret) {
       throw ParseException("bad const", s[1]->line, s[1]->col);
@@ -1165,7 +1165,7 @@ Expression* SExpressionWasmBuilder::makeConst(Element& s, Type type) {
   size_t lanes = s.size() - 2;
   switch (lanes) {
     case 2: {
-      if (lane_t != i64 && lane_t != f64) {
+      if (lane_t != Type::i64 && lane_t != Type::f64) {
         throw ParseException(
           "Unexpected v128 literal lane type", s[1]->line, s[1]->col);
       }
@@ -1173,7 +1173,7 @@ Expression* SExpressionWasmBuilder::makeConst(Element& s, Type type) {
       break;
     }
     case 4: {
-      if (lane_t != i32 && lane_t != f32) {
+      if (lane_t != Type::i32 && lane_t != Type::f32) {
         throw ParseException(
           "Unexpected v128 literal lane type", s[1]->line, s[1]->col);
       }
@@ -1181,7 +1181,7 @@ Expression* SExpressionWasmBuilder::makeConst(Element& s, Type type) {
       break;
     }
     case 8: {
-      if (lane_t != i32) {
+      if (lane_t != Type::i32) {
         throw ParseException(
           "Unexpected v128 literal lane type", s[1]->line, s[1]->col);
       }
@@ -1189,7 +1189,7 @@ Expression* SExpressionWasmBuilder::makeConst(Element& s, Type type) {
       break;
     }
     case 16: {
-      if (lane_t != i32) {
+      if (lane_t != Type::i32) {
         throw ParseException(
           "Unexpected v128 literal lane type", s[1]->line, s[1]->col);
       }
@@ -1626,7 +1626,7 @@ SExpressionWasmBuilder::makeMaybeBlock(Element& s, size_t i, Type type) {
 
 Type SExpressionWasmBuilder::parseOptionalResultType(Element& s, Index& i) {
   if (s.size() == i) {
-    return none;
+    return Type::none;
   }
 
   // TODO(sbc): Remove support for old result syntax (bare streing) once the
@@ -1638,7 +1638,7 @@ Type SExpressionWasmBuilder::parseOptionalResultType(Element& s, Index& i) {
   Element& params = *s[i];
   IString id = params[0]->str();
   if (id != RESULT) {
-    return none;
+    return Type::none;
   }
 
   i++;
@@ -2003,7 +2003,7 @@ void SExpressionWasmBuilder::parseMemory(Element& s, bool preParseImport) {
     }
     const char* input = curr[j]->c_str();
     auto* offset = allocator.alloc<Const>();
-    offset->type = i32;
+    offset->type = Type::i32;
     offset->value = Literal(int32_t(offsetValue));
     if (auto size = strlen(input)) {
       std::vector<char> data;
@@ -2245,7 +2245,7 @@ void SExpressionWasmBuilder::parseGlobal(Element& s, bool preParseImport) {
   globalCounter++;
   globalNames.push_back(global->name);
   bool mutable_ = false;
-  Type type = none;
+  Type type = Type::none;
   bool exported = false;
   Name importModule, importBase;
   while (i < s.size() && s[i]->isList()) {
@@ -2276,7 +2276,7 @@ void SExpressionWasmBuilder::parseGlobal(Element& s, bool preParseImport) {
   if (exported && mutable_) {
     throw ParseException("cannot export a mutable global", s.line, s.col);
   }
-  if (type == none) {
+  if (type == Type::none) {
     type = stringToType(s[i++]->str());
   }
   if (importModule.is()) {
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index af1e8907c..551b1f132 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -21,7 +21,7 @@ namespace wasm {
 void BinaryInstWriter::visitBlock(Block* curr) {
   breakStack.push_back(curr->name);
   o << int8_t(BinaryConsts::Block);
-  o << binaryType(curr->type != unreachable ? curr->type : none);
+  o << binaryType(curr->type != Type::unreachable ? curr->type : Type::none);
 }
 
 void BinaryInstWriter::visitIf(If* curr) {
@@ -30,7 +30,7 @@ void BinaryInstWriter::visitIf(If* curr) {
   // instead)
   breakStack.emplace_back(IMPOSSIBLE_CONTINUE);
   o << int8_t(BinaryConsts::If);
-  o << binaryType(curr->type != unreachable ? curr->type : none);
+  o << binaryType(curr->type != Type::unreachable ? curr->type : Type::none);
 }
 
 void BinaryInstWriter::emitIfElse() {
@@ -43,7 +43,7 @@ void BinaryInstWriter::emitIfElse() {
 void BinaryInstWriter::visitLoop(Loop* curr) {
   breakStack.push_back(curr->name);
   o << int8_t(BinaryConsts::Loop);
-  o << binaryType(curr->type != unreachable ? curr->type : none);
+  o << binaryType(curr->type != Type::unreachable ? curr->type : Type::none);
 }
 
 void BinaryInstWriter::visitBreak(Break* curr) {
@@ -94,7 +94,7 @@ void BinaryInstWriter::visitGlobalSet(GlobalSet* curr) {
 void BinaryInstWriter::visitLoad(Load* curr) {
   if (!curr->isAtomic) {
     switch (curr->type) {
-      case i32: {
+      case Type::i32: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(curr->signed_ ? BinaryConsts::I32LoadMem8S
@@ -112,7 +112,7 @@ void BinaryInstWriter::visitLoad(Load* curr) {
         }
         break;
       }
-      case i64: {
+      case Type::i64: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(curr->signed_ ? BinaryConsts::I64LoadMem8S
@@ -134,30 +134,30 @@ void BinaryInstWriter::visitLoad(Load* curr) {
         }
         break;
       }
-      case f32:
+      case Type::f32:
         o << int8_t(BinaryConsts::F32LoadMem);
         break;
-      case f64:
+      case Type::f64:
         o << int8_t(BinaryConsts::F64LoadMem);
         break;
-      case v128:
+      case Type::v128:
         o << int8_t(BinaryConsts::SIMDPrefix) << U32LEB(BinaryConsts::V128Load);
         break;
-      case unreachable:
+      case Type::unreachable:
         // the pointer is unreachable, so we are never reached; just don't emit
         // a load
         return;
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
         WASM_UNREACHABLE("unexpected type");
     }
   } else {
     o << int8_t(BinaryConsts::AtomicPrefix);
     switch (curr->type) {
-      case i32: {
+      case Type::i32: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I32AtomicLoad8U);
@@ -173,7 +173,7 @@ void BinaryInstWriter::visitLoad(Load* curr) {
         }
         break;
       }
-      case i64: {
+      case Type::i64: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I64AtomicLoad8U);
@@ -192,7 +192,7 @@ void BinaryInstWriter::visitLoad(Load* curr) {
         }
         break;
       }
-      case unreachable:
+      case Type::unreachable:
         return;
       default:
         WASM_UNREACHABLE("unexpected type");
@@ -204,7 +204,7 @@ void BinaryInstWriter::visitLoad(Load* curr) {
 void BinaryInstWriter::visitStore(Store* curr) {
   if (!curr->isAtomic) {
     switch (curr->valueType) {
-      case i32: {
+      case Type::i32: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I32StoreMem8);
@@ -220,7 +220,7 @@ void BinaryInstWriter::visitStore(Store* curr) {
         }
         break;
       }
-      case i64: {
+      case Type::i64: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I64StoreMem8);
@@ -239,28 +239,28 @@ void BinaryInstWriter::visitStore(Store* curr) {
         }
         break;
       }
-      case f32:
+      case Type::f32:
         o << int8_t(BinaryConsts::F32StoreMem);
         break;
-      case f64:
+      case Type::f64:
         o << int8_t(BinaryConsts::F64StoreMem);
         break;
-      case v128:
+      case Type::v128:
         o << int8_t(BinaryConsts::SIMDPrefix)
           << U32LEB(BinaryConsts::V128Store);
         break;
-      case funcref:
-      case anyref:
-      case nullref:
-      case exnref:
-      case none:
-      case unreachable:
+      case Type::funcref:
+      case Type::anyref:
+      case Type::nullref:
+      case Type::exnref:
+      case Type::none:
+      case Type::unreachable:
         WASM_UNREACHABLE("unexpected type");
     }
   } else {
     o << int8_t(BinaryConsts::AtomicPrefix);
     switch (curr->valueType) {
-      case i32: {
+      case Type::i32: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I32AtomicStore8);
@@ -276,7 +276,7 @@ void BinaryInstWriter::visitStore(Store* curr) {
         }
         break;
       }
-      case i64: {
+      case Type::i64: {
         switch (curr->bytes) {
           case 1:
             o << int8_t(BinaryConsts::I64AtomicStore8);
@@ -308,7 +308,7 @@ void BinaryInstWriter::visitAtomicRMW(AtomicRMW* curr) {
 #define CASE_FOR_OP(Op)                                                        \
   case Op:                                                                     \
     switch (curr->type) {                                                      \
-      case i32:                                                                \
+      case Type::i32:                                                          \
         switch (curr->bytes) {                                                 \
           case 1:                                                              \
             o << int8_t(BinaryConsts::I32AtomicRMW##Op##8U);                   \
@@ -323,7 +323,7 @@ void BinaryInstWriter::visitAtomicRMW(AtomicRMW* curr) {
             WASM_UNREACHABLE("invalid rmw size");                              \
         }                                                                      \
         break;                                                                 \
-      case i64:                                                                \
+      case Type::i64:                                                          \
         switch (curr->bytes) {                                                 \
           case 1:                                                              \
             o << int8_t(BinaryConsts::I64AtomicRMW##Op##8U);                   \
@@ -364,7 +364,7 @@ void BinaryInstWriter::visitAtomicRMW(AtomicRMW* curr) {
 void BinaryInstWriter::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
   o << int8_t(BinaryConsts::AtomicPrefix);
   switch (curr->type) {
-    case i32:
+    case Type::i32:
       switch (curr->bytes) {
         case 1:
           o << int8_t(BinaryConsts::I32AtomicCmpxchg8U);
@@ -379,7 +379,7 @@ void BinaryInstWriter::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
           WASM_UNREACHABLE("invalid size");
       }
       break;
-    case i64:
+    case Type::i64:
       switch (curr->bytes) {
         case 1:
           o << int8_t(BinaryConsts::I64AtomicCmpxchg8U);
@@ -406,12 +406,12 @@ void BinaryInstWriter::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
 void BinaryInstWriter::visitAtomicWait(AtomicWait* curr) {
   o << int8_t(BinaryConsts::AtomicPrefix);
   switch (curr->expectedType) {
-    case i32: {
+    case Type::i32: {
       o << int8_t(BinaryConsts::I32AtomicWait);
       emitMemoryAccess(4, 4, curr->offset);
       break;
     }
-    case i64: {
+    case Type::i64: {
       o << int8_t(BinaryConsts::I64AtomicWait);
       emitMemoryAccess(8, 8, curr->offset);
       break;
@@ -622,23 +622,23 @@ void BinaryInstWriter::visitMemoryFill(MemoryFill* curr) {
 
 void BinaryInstWriter::visitConst(Const* curr) {
   switch (curr->type) {
-    case i32: {
+    case Type::i32: {
       o << int8_t(BinaryConsts::I32Const) << S32LEB(curr->value.geti32());
       break;
     }
-    case i64: {
+    case Type::i64: {
       o << int8_t(BinaryConsts::I64Const) << S64LEB(curr->value.geti64());
       break;
     }
-    case f32: {
+    case Type::f32: {
       o << int8_t(BinaryConsts::F32Const) << curr->value.reinterpreti32();
       break;
     }
-    case f64: {
+    case Type::f64: {
       o << int8_t(BinaryConsts::F64Const) << curr->value.reinterpreti64();
       break;
     }
-    case v128: {
+    case Type::v128: {
       o << int8_t(BinaryConsts::SIMDPrefix) << U32LEB(BinaryConsts::V128Const);
       std::array<uint8_t, 16> v = curr->value.getv128();
       for (size_t i = 0; i < 16; ++i) {
@@ -646,12 +646,12 @@ void BinaryInstWriter::visitConst(Const* curr) {
       }
       break;
     }
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
-    case none:
-    case unreachable:
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
+    case Type::none:
+    case Type::unreachable:
       WASM_UNREACHABLE("unexpected type");
   }
 }
@@ -1592,7 +1592,7 @@ void BinaryInstWriter::visitRefFunc(RefFunc* curr) {
 void BinaryInstWriter::visitTry(Try* curr) {
   breakStack.emplace_back(IMPOSSIBLE_CONTINUE);
   o << int8_t(BinaryConsts::Try);
-  o << binaryType(curr->type != unreachable ? curr->type : none);
+  o << binaryType(curr->type != Type::unreachable ? curr->type : Type::none);
 }
 
 void BinaryInstWriter::emitCatch() {
@@ -1661,85 +1661,88 @@ void BinaryInstWriter::mapLocalsAndEmitHeader() {
     Type type = func->getLocalType(i);
     // increment now for simplicity, must decrement it in returns
     currLocalsByType[type]++;
-    if (type == i32) {
-      mappedLocals[i] = index + currLocalsByType[i32] - 1;
+    if (type == Type::i32) {
+      mappedLocals[i] = index + currLocalsByType[Type::i32] - 1;
       continue;
     }
-    index += numLocalsByType[i32];
-    if (type == i64) {
-      mappedLocals[i] = index + currLocalsByType[i64] - 1;
+    index += numLocalsByType[Type::i32];
+    if (type == Type::i64) {
+      mappedLocals[i] = index + currLocalsByType[Type::i64] - 1;
       continue;
     }
-    index += numLocalsByType[i64];
-    if (type == f32) {
-      mappedLocals[i] = index + currLocalsByType[f32] - 1;
+    index += numLocalsByType[Type::i64];
+    if (type == Type::f32) {
+      mappedLocals[i] = index + currLocalsByType[Type::f32] - 1;
       continue;
     }
-    index += numLocalsByType[f32];
-    if (type == f64) {
-      mappedLocals[i] = index + currLocalsByType[f64] - 1;
+    index += numLocalsByType[Type::f32];
+    if (type == Type::f64) {
+      mappedLocals[i] = index + currLocalsByType[Type::f64] - 1;
       continue;
     }
-    index += numLocalsByType[f64];
-    if (type == v128) {
-      mappedLocals[i] = index + currLocalsByType[v128] - 1;
+    index += numLocalsByType[Type::f64];
+    if (type == Type::v128) {
+      mappedLocals[i] = index + currLocalsByType[Type::v128] - 1;
       continue;
     }
-    index += numLocalsByType[v128];
-    if (type == funcref) {
-      mappedLocals[i] = index + currLocalsByType[funcref] - 1;
+    index += numLocalsByType[Type::v128];
+    if (type == Type::funcref) {
+      mappedLocals[i] = index + currLocalsByType[Type::funcref] - 1;
       continue;
     }
-    index += numLocalsByType[funcref];
-    if (type == anyref) {
-      mappedLocals[i] = index + currLocalsByType[anyref] - 1;
+    index += numLocalsByType[Type::funcref];
+    if (type == Type::anyref) {
+      mappedLocals[i] = index + currLocalsByType[Type::anyref] - 1;
       continue;
     }
-    index += numLocalsByType[anyref];
-    if (type == nullref) {
-      mappedLocals[i] = index + currLocalsByType[nullref] - 1;
+    index += numLocalsByType[Type::anyref];
+    if (type == Type::nullref) {
+      mappedLocals[i] = index + currLocalsByType[Type::nullref] - 1;
       continue;
     }
-    index += numLocalsByType[nullref];
-    if (type == exnref) {
-      mappedLocals[i] = index + currLocalsByType[exnref] - 1;
+    index += numLocalsByType[Type::nullref];
+    if (type == Type::exnref) {
+      mappedLocals[i] = index + currLocalsByType[Type::exnref] - 1;
       continue;
     }
     WASM_UNREACHABLE("unexpected type");
   }
   // Emit them.
-  o << U32LEB(
-    (numLocalsByType[i32] ? 1 : 0) + (numLocalsByType[i64] ? 1 : 0) +
-    (numLocalsByType[f32] ? 1 : 0) + (numLocalsByType[f64] ? 1 : 0) +
-    (numLocalsByType[v128] ? 1 : 0) + (numLocalsByType[funcref] ? 1 : 0) +
-    (numLocalsByType[anyref] ? 1 : 0) + (numLocalsByType[nullref] ? 1 : 0) +
-    (numLocalsByType[exnref] ? 1 : 0));
-  if (numLocalsByType[i32]) {
-    o << U32LEB(numLocalsByType[i32]) << binaryType(i32);
+  o << U32LEB((numLocalsByType[Type::i32] ? 1 : 0) +
+              (numLocalsByType[Type::i64] ? 1 : 0) +
+              (numLocalsByType[Type::f32] ? 1 : 0) +
+              (numLocalsByType[Type::f64] ? 1 : 0) +
+              (numLocalsByType[Type::v128] ? 1 : 0) +
+              (numLocalsByType[Type::funcref] ? 1 : 0) +
+              (numLocalsByType[Type::anyref] ? 1 : 0) +
+              (numLocalsByType[Type::nullref] ? 1 : 0) +
+              (numLocalsByType[Type::exnref] ? 1 : 0));
+  if (numLocalsByType[Type::i32]) {
+    o << U32LEB(numLocalsByType[Type::i32]) << binaryType(Type::i32);
   }
-  if (numLocalsByType[i64]) {
-    o << U32LEB(numLocalsByType[i64]) << binaryType(i64);
+  if (numLocalsByType[Type::i64]) {
+    o << U32LEB(numLocalsByType[Type::i64]) << binaryType(Type::i64);
   }
-  if (numLocalsByType[f32]) {
-    o << U32LEB(numLocalsByType[f32]) << binaryType(f32);
+  if (numLocalsByType[Type::f32]) {
+    o << U32LEB(numLocalsByType[Type::f32]) << binaryType(Type::f32);
   }
-  if (numLocalsByType[f64]) {
-    o << U32LEB(numLocalsByType[f64]) << binaryType(f64);
+  if (numLocalsByType[Type::f64]) {
+    o << U32LEB(numLocalsByType[Type::f64]) << binaryType(Type::f64);
   }
-  if (numLocalsByType[v128]) {
-    o << U32LEB(numLocalsByType[v128]) << binaryType(v128);
+  if (numLocalsByType[Type::v128]) {
+    o << U32LEB(numLocalsByType[Type::v128]) << binaryType(Type::v128);
   }
-  if (numLocalsByType[funcref]) {
-    o << U32LEB(numLocalsByType[funcref]) << binaryType(funcref);
+  if (numLocalsByType[Type::funcref]) {
+    o << U32LEB(numLocalsByType[Type::funcref]) << binaryType(Type::funcref);
   }
-  if (numLocalsByType[anyref]) {
-    o << U32LEB(numLocalsByType[anyref]) << binaryType(anyref);
+  if (numLocalsByType[Type::anyref]) {
+    o << U32LEB(numLocalsByType[Type::anyref]) << binaryType(Type::anyref);
   }
-  if (numLocalsByType[nullref]) {
-    o << U32LEB(numLocalsByType[nullref]) << binaryType(nullref);
+  if (numLocalsByType[Type::nullref]) {
+    o << U32LEB(numLocalsByType[Type::nullref]) << binaryType(Type::nullref);
   }
-  if (numLocalsByType[exnref]) {
-    o << U32LEB(numLocalsByType[exnref]) << binaryType(exnref);
+  if (numLocalsByType[Type::exnref]) {
+    o << U32LEB(numLocalsByType[Type::exnref]) << binaryType(Type::exnref);
   }
 }
 
@@ -1799,17 +1802,17 @@ StackInst* StackIRGenerator::makeStackInst(StackInst::Op op,
   auto stackType = origin->type;
   if (origin->is<Block>() || origin->is<Loop>() || origin->is<If>() ||
       origin->is<Try>()) {
-    if (stackType == unreachable) {
+    if (stackType == Type::unreachable) {
       // There are no unreachable blocks, loops, or ifs. we emit extra
       // unreachables to fix that up, so that they are valid as having none
       // type.
-      stackType = none;
+      stackType = Type::none;
     } else if (op != StackInst::BlockEnd && op != StackInst::IfEnd &&
                op != StackInst::LoopEnd && op != StackInst::TryEnd) {
       // If a concrete type is returned, we mark the end of the construct has
       // having that type (as it is pushed to the value stack at that point),
       // other parts are marked as none).
-      stackType = none;
+      stackType = Type::none;
     }
   }
   ret->type = stackType;
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index b19ed096f..30e182f0b 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -147,7 +147,7 @@ struct ValidationInfo {
   template<typename T, typename S>
   bool shouldBeEqualOrFirstIsUnreachable(
     S left, S right, T curr, const char* text, Function* func = nullptr) {
-    if (left != unreachable && left != right) {
+    if (left != Type::unreachable && left != right) {
       std::ostringstream ss;
       ss << left << " != " << right << ": " << text;
       fail(ss.str(), curr, func);
@@ -173,9 +173,9 @@ struct ValidationInfo {
                                 const char* text,
                                 Function* func = nullptr) {
     switch (ty) {
-      case i32:
-      case i64:
-      case unreachable: {
+      case Type::i32:
+      case Type::i64:
+      case Type::unreachable: {
         break;
       }
       default:
@@ -411,7 +411,8 @@ void FunctionValidator::visitBlock(Block* curr) {
           curr,
           "block+breaks must have right type if breaks return a value");
       }
-      if (curr->type.isConcrete() && info.arity && info.type != unreachable) {
+      if (curr->type.isConcrete() && info.arity &&
+          info.type != Type::unreachable) {
         shouldBeSubType(
           info.type,
           curr->type,
@@ -422,7 +423,7 @@ void FunctionValidator::visitBlock(Block* curr) {
         info.arity != BreakInfo::PoisonArity, curr, "break arities must match");
       if (curr->list.size() > 0) {
         auto last = curr->list.back()->type;
-        if (last == none) {
+        if (last == Type::none) {
           shouldBeTrue(info.arity == Index(0),
                        curr,
                        "if block ends with a none, breaks cannot send a value "
@@ -463,7 +464,7 @@ void FunctionValidator::visitBlock(Block* curr) {
       } else {
         shouldBeUnequal(
           backType,
-          none,
+          Type(Type::none),
           curr,
           "block with value must not have last element that is none");
       }
@@ -487,7 +488,7 @@ void FunctionValidator::visitLoop(Loop* curr) {
     }
     breakInfos.erase(iter);
   }
-  if (curr->type == none) {
+  if (curr->type == Type::none) {
     shouldBeFalse(curr->body->type.isConcrete(),
                   curr,
                   "bad body for a loop that has no value");
@@ -513,22 +514,22 @@ void FunctionValidator::visitLoop(Loop* curr) {
 }
 
 void FunctionValidator::visitIf(If* curr) {
-  shouldBeTrue(curr->condition->type == unreachable ||
-                 curr->condition->type == i32,
+  shouldBeTrue(curr->condition->type == Type::unreachable ||
+                 curr->condition->type == Type::i32,
                curr,
                "if condition must be valid");
   if (!curr->ifFalse) {
     shouldBeFalse(curr->ifTrue->type.isConcrete(),
                   curr,
                   "if without else must not return a value in body");
-    if (curr->condition->type != unreachable) {
+    if (curr->condition->type != Type::unreachable) {
       shouldBeEqual(curr->type,
-                    none,
+                    Type(Type::none),
                     curr,
                     "if without else and reachable condition must be none");
     }
   } else {
-    if (curr->type != unreachable) {
+    if (curr->type != Type::unreachable) {
       shouldBeSubTypeOrFirstIsUnreachable(
         curr->ifTrue->type,
         curr->type,
@@ -540,13 +541,13 @@ void FunctionValidator::visitIf(If* curr) {
         curr,
         "returning if-else's false must have right type");
     } else {
-      if (curr->condition->type != unreachable) {
+      if (curr->condition->type != Type::unreachable) {
         shouldBeEqual(curr->ifTrue->type,
-                      unreachable,
+                      Type(Type::unreachable),
                       curr,
                       "unreachable if-else must have unreachable true");
         shouldBeEqual(curr->ifFalse->type,
-                      unreachable,
+                      Type(Type::unreachable),
                       curr,
                       "unreachable if-else must have unreachable false");
       }
@@ -570,14 +571,15 @@ void FunctionValidator::noteBreak(Name name,
                                   Expression* value,
                                   Expression* curr) {
   if (value) {
-    shouldBeUnequal(value->type, none, curr, "breaks must have a valid value");
+    shouldBeUnequal(
+      value->type, Type(Type::none), curr, "breaks must have a valid value");
   }
-  noteBreak(name, value ? value->type : none, curr);
+  noteBreak(name, value ? value->type : Type::none, curr);
 }
 
 void FunctionValidator::noteBreak(Name name, Type valueType, Expression* curr) {
   Index arity = 0;
-  if (valueType != none) {
+  if (valueType != Type::none) {
     arity = 1;
   }
   auto iter = breakInfos.find(name);
@@ -598,12 +600,13 @@ void FunctionValidator::noteBreak(Name name, Type valueType, Expression* curr) {
 void FunctionValidator::visitBreak(Break* curr) {
   noteBreak(curr->name, curr->value, curr);
   if (curr->value) {
-    shouldBeTrue(
-      curr->value->type != none, curr, "break value must not have none type");
+    shouldBeTrue(curr->value->type != Type::none,
+                 curr,
+                 "break value must not have none type");
   }
   if (curr->condition) {
-    shouldBeTrue(curr->condition->type == unreachable ||
-                   curr->condition->type == i32,
+    shouldBeTrue(curr->condition->type == Type::unreachable ||
+                   curr->condition->type == Type::i32,
                  curr,
                  "break condition must be i32");
   }
@@ -614,8 +617,8 @@ void FunctionValidator::visitSwitch(Switch* curr) {
     noteBreak(target, curr->value, curr);
   }
   noteBreak(curr->default_, curr->value, curr);
-  shouldBeTrue(curr->condition->type == unreachable ||
-                 curr->condition->type == i32,
+  shouldBeTrue(curr->condition->type == Type::unreachable ||
+                 curr->condition->type == Type::i32,
                curr,
                "br_table condition must be i32");
 }
@@ -648,7 +651,7 @@ void FunctionValidator::visitCall(Call* curr) {
   }
   if (curr->isReturn) {
     shouldBeEqual(curr->type,
-                  unreachable,
+                  Type(Type::unreachable),
                   curr,
                   "return_call should have unreachable type");
     shouldBeEqual(
@@ -657,11 +660,11 @@ void FunctionValidator::visitCall(Call* curr) {
       curr,
       "return_call callee return type must match caller return type");
   } else {
-    if (curr->type == unreachable) {
-      bool hasUnreachableOperand =
-        std::any_of(curr->operands.begin(),
-                    curr->operands.end(),
-                    [](Expression* op) { return op->type == unreachable; });
+    if (curr->type == Type::unreachable) {
+      bool hasUnreachableOperand = std::any_of(
+        curr->operands.begin(), curr->operands.end(), [](Expression* op) {
+          return op->type == Type::unreachable;
+        });
       shouldBeTrue(
         hasUnreachableOperand,
         curr,
@@ -683,8 +686,10 @@ void FunctionValidator::visitCallIndirect(CallIndirect* curr) {
     return;
   }
   const std::vector<Type>& params = curr->sig.params.expand();
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->target->type, i32, curr, "indirect call target must be an i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->target->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "indirect call target must be an i32");
   if (!shouldBeTrue(curr->operands.size() == params.size(),
                     curr,
                     "call param number must match")) {
@@ -701,7 +706,7 @@ void FunctionValidator::visitCallIndirect(CallIndirect* curr) {
   }
   if (curr->isReturn) {
     shouldBeEqual(curr->type,
-                  unreachable,
+                  Type(Type::unreachable),
                   curr,
                   "return_call_indirect should have unreachable type");
     shouldBeEqual(
@@ -710,12 +715,12 @@ void FunctionValidator::visitCallIndirect(CallIndirect* curr) {
       curr,
       "return_call_indirect callee return type must match caller return type");
   } else {
-    if (curr->type == unreachable) {
-      if (curr->target->type != unreachable) {
-        bool hasUnreachableOperand =
-          std::any_of(curr->operands.begin(),
-                      curr->operands.end(),
-                      [](Expression* op) { return op->type == unreachable; });
+    if (curr->type == Type::unreachable) {
+      if (curr->target->type != Type::unreachable) {
+        bool hasUnreachableOperand = std::any_of(
+          curr->operands.begin(), curr->operands.end(), [](Expression* op) {
+            return op->type == Type::unreachable;
+          });
         shouldBeTrue(hasUnreachableOperand,
                      curr,
                      "call_indirects may only be unreachable if they have "
@@ -754,8 +759,8 @@ void FunctionValidator::visitLocalSet(LocalSet* curr) {
   if (shouldBeTrue(curr->index < getFunction()->getNumLocals(),
                    curr,
                    "local.set index must be small enough")) {
-    if (curr->value->type != unreachable) {
-      if (curr->type != none) { // tee is ok anyhow
+    if (curr->value->type != Type::unreachable) {
+      if (curr->type != Type::none) { // tee is ok anyhow
         shouldBeEqual(getFunction()->getLocalType(curr->index),
                       curr->type,
                       curr,
@@ -803,12 +808,12 @@ void FunctionValidator::visitLoad(Load* curr) {
     shouldBeTrue(getModule()->features.hasAtomics(),
                  curr,
                  "Atomic operation (atomics are disabled)");
-    shouldBeTrue(curr->type == i32 || curr->type == i64 ||
-                   curr->type == unreachable,
+    shouldBeTrue(curr->type == Type::i32 || curr->type == Type::i64 ||
+                   curr->type == Type::unreachable,
                  curr,
                  "Atomic load should be i32 or i64");
   }
-  if (curr->type == v128) {
+  if (curr->type == Type::v128) {
     shouldBeTrue(getModule()->features.hasSIMD(),
                  curr,
                  "SIMD operation (SIMD is disabled)");
@@ -819,7 +824,7 @@ void FunctionValidator::visitLoad(Load* curr) {
   validateMemBytes(curr->bytes, curr->type, curr);
   validateAlignment(curr->align, curr->type, curr->bytes, curr->isAtomic, curr);
   shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "load pointer type must be i32");
+    curr->ptr->type, Type(Type::i32), curr, "load pointer type must be i32");
   if (curr->isAtomic) {
     shouldBeFalse(curr->signed_, curr, "atomic loads must be unsigned");
     shouldBeIntOrUnreachable(
@@ -834,12 +839,12 @@ void FunctionValidator::visitStore(Store* curr) {
     shouldBeTrue(getModule()->features.hasAtomics(),
                  curr,
                  "Atomic operation (atomics are disabled)");
-    shouldBeTrue(curr->valueType == i32 || curr->valueType == i64 ||
-                   curr->valueType == unreachable,
+    shouldBeTrue(curr->valueType == Type::i32 || curr->valueType == Type::i64 ||
+                   curr->valueType == Type::unreachable,
                  curr,
                  "Atomic store should be i32 or i64");
   }
-  if (curr->valueType == v128) {
+  if (curr->valueType == Type::v128) {
     shouldBeTrue(getModule()->features.hasSIMD(),
                  curr,
                  "SIMD operation (SIMD is disabled)");
@@ -851,9 +856,11 @@ void FunctionValidator::visitStore(Store* curr) {
   validateAlignment(
     curr->align, curr->valueType, curr->bytes, curr->isAtomic, curr);
   shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "store pointer type must be i32");
-  shouldBeUnequal(
-    curr->value->type, none, curr, "store value type must not be none");
+    curr->ptr->type, Type(Type::i32), curr, "store pointer type must be i32");
+  shouldBeUnequal(curr->value->type,
+                  Type(Type::none),
+                  curr,
+                  "store value type must not be none");
   shouldBeEqualOrFirstIsUnreachable(
     curr->value->type, curr->valueType, curr, "store value type must match");
   if (curr->isAtomic) {
@@ -872,8 +879,10 @@ void FunctionValidator::visitAtomicRMW(AtomicRMW* curr) {
                 curr,
                 "Atomic operation with non-shared memory");
   validateMemBytes(curr->bytes, curr->type, curr);
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "AtomicRMW pointer type must be i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->ptr->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "AtomicRMW pointer type must be i32");
   shouldBeEqualOrFirstIsUnreachable(curr->type,
                                     curr->value->type,
                                     curr,
@@ -893,9 +902,9 @@ void FunctionValidator::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
                 "Atomic operation with non-shared memory");
   validateMemBytes(curr->bytes, curr->type, curr);
   shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "cmpxchg pointer type must be i32");
-  if (curr->expected->type != unreachable &&
-      curr->replacement->type != unreachable) {
+    curr->ptr->type, Type(Type::i32), curr, "cmpxchg pointer type must be i32");
+  if (curr->expected->type != Type::unreachable &&
+      curr->replacement->type != Type::unreachable) {
     shouldBeEqual(curr->expected->type,
                   curr->replacement->type,
                   curr,
@@ -925,9 +934,11 @@ void FunctionValidator::visitAtomicWait(AtomicWait* curr) {
                 curr,
                 "Atomic operation with non-shared memory");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, i32, curr, "AtomicWait must have type i32");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "AtomicWait pointer type must be i32");
+    curr->type, Type(Type::i32), curr, "AtomicWait must have type i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->ptr->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "AtomicWait pointer type must be i32");
   shouldBeIntOrUnreachable(
     curr->expected->type, curr, "AtomicWait expected type must be int");
   shouldBeEqualOrFirstIsUnreachable(
@@ -935,8 +946,10 @@ void FunctionValidator::visitAtomicWait(AtomicWait* curr) {
     curr->expectedType,
     curr,
     "AtomicWait expected type must match operand");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->timeout->type, i64, curr, "AtomicWait timeout type must be i64");
+  shouldBeEqualOrFirstIsUnreachable(curr->timeout->type,
+                                    Type(Type::i64),
+                                    curr,
+                                    "AtomicWait timeout type must be i64");
 }
 
 void FunctionValidator::visitAtomicNotify(AtomicNotify* curr) {
@@ -949,12 +962,14 @@ void FunctionValidator::visitAtomicNotify(AtomicNotify* curr) {
                 curr,
                 "Atomic operation with non-shared memory");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, i32, curr, "AtomicNotify must have type i32");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "AtomicNotify pointer type must be i32");
+    curr->type, Type(Type::i32), curr, "AtomicNotify must have type i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->ptr->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "AtomicNotify pointer type must be i32");
   shouldBeEqualOrFirstIsUnreachable(
     curr->notifyCount->type,
-    i32,
+    Type(Type::i32),
     curr,
     "AtomicNotify notifyCount type must be i32");
 }
@@ -977,35 +992,37 @@ void FunctionValidator::visitAtomicFence(AtomicFence* curr) {
 void FunctionValidator::visitSIMDExtract(SIMDExtract* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->vec->type, v128, curr, "extract_lane must operate on a v128");
-  Type lane_t = none;
+  shouldBeEqualOrFirstIsUnreachable(curr->vec->type,
+                                    Type(Type::v128),
+                                    curr,
+                                    "extract_lane must operate on a v128");
+  Type lane_t = Type::none;
   size_t lanes = 0;
   switch (curr->op) {
     case ExtractLaneSVecI8x16:
     case ExtractLaneUVecI8x16:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 16;
       break;
     case ExtractLaneSVecI16x8:
     case ExtractLaneUVecI16x8:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 8;
       break;
     case ExtractLaneVecI32x4:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 4;
       break;
     case ExtractLaneVecI64x2:
-      lane_t = i64;
+      lane_t = Type::i64;
       lanes = 2;
       break;
     case ExtractLaneVecF32x4:
-      lane_t = f32;
+      lane_t = Type::f32;
       lanes = 4;
       break;
     case ExtractLaneVecF64x2:
-      lane_t = f64;
+      lane_t = Type::f64;
       lanes = 2;
       break;
   }
@@ -1021,34 +1038,36 @@ void FunctionValidator::visitSIMDReplace(SIMDReplace* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, v128, curr, "replace_lane must have type v128");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->vec->type, v128, curr, "replace_lane must operate on a v128");
-  Type lane_t = none;
+    curr->type, Type(Type::v128), curr, "replace_lane must have type v128");
+  shouldBeEqualOrFirstIsUnreachable(curr->vec->type,
+                                    Type(Type::v128),
+                                    curr,
+                                    "replace_lane must operate on a v128");
+  Type lane_t = Type::none;
   size_t lanes = 0;
   switch (curr->op) {
     case ReplaceLaneVecI8x16:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 16;
       break;
     case ReplaceLaneVecI16x8:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 8;
       break;
     case ReplaceLaneVecI32x4:
-      lane_t = i32;
+      lane_t = Type::i32;
       lanes = 4;
       break;
     case ReplaceLaneVecI64x2:
-      lane_t = i64;
+      lane_t = Type::i64;
       lanes = 2;
       break;
     case ReplaceLaneVecF32x4:
-      lane_t = f32;
+      lane_t = Type::f32;
       lanes = 4;
       break;
     case ReplaceLaneVecF64x2:
-      lane_t = f64;
+      lane_t = Type::f64;
       lanes = 2;
       break;
   }
@@ -1061,11 +1080,11 @@ void FunctionValidator::visitSIMDShuffle(SIMDShuffle* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, v128, curr, "v128.shuffle must have type v128");
+    curr->type, Type(Type::v128), curr, "v128.shuffle must have type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->left->type, v128, curr, "expected operand of type v128");
+    curr->left->type, Type(Type::v128), curr, "expected operand of type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->right->type, v128, curr, "expected operand of type v128");
+    curr->right->type, Type(Type::v128), curr, "expected operand of type v128");
   for (uint8_t index : curr->mask) {
     shouldBeTrue(index < 32, curr, "Invalid lane index in mask");
   }
@@ -1075,24 +1094,26 @@ void FunctionValidator::visitSIMDTernary(SIMDTernary* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, v128, curr, "SIMD ternary must have type v128");
+    curr->type, Type(Type::v128), curr, "SIMD ternary must have type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->a->type, v128, curr, "expected operand of type v128");
+    curr->a->type, Type(Type::v128), curr, "expected operand of type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->b->type, v128, curr, "expected operand of type v128");
+    curr->b->type, Type(Type::v128), curr, "expected operand of type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->c->type, v128, curr, "expected operand of type v128");
+    curr->c->type, Type(Type::v128), curr, "expected operand of type v128");
 }
 
 void FunctionValidator::visitSIMDShift(SIMDShift* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, v128, curr, "vector shift must have type v128");
+    curr->type, Type(Type::v128), curr, "vector shift must have type v128");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->vec->type, v128, curr, "expected operand of type v128");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->shift->type, i32, curr, "expected shift amount to have type i32");
+    curr->vec->type, Type(Type::v128), curr, "expected operand of type v128");
+  shouldBeEqualOrFirstIsUnreachable(curr->shift->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "expected shift amount to have type i32");
 }
 
 void FunctionValidator::visitSIMDLoad(SIMDLoad* curr) {
@@ -1101,15 +1122,17 @@ void FunctionValidator::visitSIMDLoad(SIMDLoad* curr) {
   shouldBeTrue(
     getModule()->features.hasSIMD(), curr, "SIMD operation (SIMD is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, v128, curr, "load_splat must have type v128");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->ptr->type, i32, curr, "load_splat address must have type i32");
-  Type memAlignType = none;
+    curr->type, Type(Type::v128), curr, "load_splat must have type v128");
+  shouldBeEqualOrFirstIsUnreachable(curr->ptr->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "load_splat address must have type i32");
+  Type memAlignType = Type::none;
   switch (curr->op) {
     case LoadSplatVec8x16:
     case LoadSplatVec16x8:
     case LoadSplatVec32x4:
-      memAlignType = i32;
+      memAlignType = Type::i32;
       break;
     case LoadSplatVec64x2:
     case LoadExtSVec8x8ToVecI16x8:
@@ -1118,7 +1141,7 @@ void FunctionValidator::visitSIMDLoad(SIMDLoad* curr) {
     case LoadExtUVec16x4ToVecI32x4:
     case LoadExtSVec32x2ToVecI64x2:
     case LoadExtUVec32x2ToVecI64x2:
-      memAlignType = i64;
+      memAlignType = Type::i64;
       break;
   }
   Index bytes = curr->getMemBytes();
@@ -1130,13 +1153,15 @@ void FunctionValidator::visitMemoryInit(MemoryInit* curr) {
                curr,
                "Bulk memory operation (bulk memory is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, none, curr, "memory.init must have type none");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->dest->type, i32, curr, "memory.init dest must be an i32");
+    curr->type, Type(Type::none), curr, "memory.init must have type none");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->offset->type, i32, curr, "memory.init offset must be an i32");
+    curr->dest->type, Type(Type::i32), curr, "memory.init dest must be an i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->offset->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "memory.init offset must be an i32");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->size->type, i32, curr, "memory.init size must be an i32");
+    curr->size->type, Type(Type::i32), curr, "memory.init size must be an i32");
   if (!shouldBeTrue(getModule()->memory.exists,
                     curr,
                     "Memory operations require a memory")) {
@@ -1152,7 +1177,7 @@ void FunctionValidator::visitDataDrop(DataDrop* curr) {
                curr,
                "Bulk memory operation (bulk memory is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, none, curr, "data.drop must have type none");
+    curr->type, Type(Type::none), curr, "data.drop must have type none");
   if (!shouldBeTrue(getModule()->memory.exists,
                     curr,
                     "Memory operations require a memory")) {
@@ -1168,13 +1193,15 @@ void FunctionValidator::visitMemoryCopy(MemoryCopy* curr) {
                curr,
                "Bulk memory operation (bulk memory is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, none, curr, "memory.copy must have type none");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->dest->type, i32, curr, "memory.copy dest must be an i32");
+    curr->type, Type(Type::none), curr, "memory.copy must have type none");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->source->type, i32, curr, "memory.copy source must be an i32");
+    curr->dest->type, Type(Type::i32), curr, "memory.copy dest must be an i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->source->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "memory.copy source must be an i32");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->size->type, i32, curr, "memory.copy size must be an i32");
+    curr->size->type, Type(Type::i32), curr, "memory.copy size must be an i32");
   shouldBeTrue(
     getModule()->memory.exists, curr, "Memory operations require a memory");
 }
@@ -1184,13 +1211,15 @@ void FunctionValidator::visitMemoryFill(MemoryFill* curr) {
                curr,
                "Bulk memory operation (bulk memory is disabled)");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->type, none, curr, "memory.fill must have type none");
-  shouldBeEqualOrFirstIsUnreachable(
-    curr->dest->type, i32, curr, "memory.fill dest must be an i32");
+    curr->type, Type(Type::none), curr, "memory.fill must have type none");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->value->type, i32, curr, "memory.fill value must be an i32");
+    curr->dest->type, Type(Type::i32), curr, "memory.fill dest must be an i32");
+  shouldBeEqualOrFirstIsUnreachable(curr->value->type,
+                                    Type(Type::i32),
+                                    curr,
+                                    "memory.fill value must be an i32");
   shouldBeEqualOrFirstIsUnreachable(
-    curr->size->type, i32, curr, "memory.fill size must be an i32");
+    curr->size->type, Type(Type::i32), curr, "memory.fill size must be an i32");
   shouldBeTrue(
     getModule()->memory.exists, curr, "Memory operations require a memory");
 }
@@ -1199,41 +1228,42 @@ void FunctionValidator::validateMemBytes(uint8_t bytes,
                                          Type type,
                                          Expression* curr) {
   switch (type) {
-    case i32:
+    case Type::i32:
       shouldBeTrue(bytes == 1 || bytes == 2 || bytes == 4,
                    curr,
                    "expected i32 operation to touch 1, 2, or 4 bytes");
       break;
-    case i64:
+    case Type::i64:
       shouldBeTrue(bytes == 1 || bytes == 2 || bytes == 4 || bytes == 8,
                    curr,
                    "expected i64 operation to touch 1, 2, 4, or 8 bytes");
       break;
-    case f32:
+    case Type::f32:
       shouldBeEqual(
         bytes, uint8_t(4), curr, "expected f32 operation to touch 4 bytes");
       break;
-    case f64:
+    case Type::f64:
       shouldBeEqual(
         bytes, uint8_t(8), curr, "expected f64 operation to touch 8 bytes");
       break;
-    case v128:
+    case Type::v128:
       shouldBeEqual(
         bytes, uint8_t(16), curr, "expected v128 operation to touch 16 bytes");
       break;
-    case unreachable:
+    case Type::unreachable:
       break;
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
-    case none:
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
+    case Type::none:
       WASM_UNREACHABLE("unexpected type");
   }
 }
 
 void FunctionValidator::visitBinary(Binary* curr) {
-  if (curr->left->type != unreachable && curr->right->type != unreachable) {
+  if (curr->left->type != Type::unreachable &&
+      curr->right->type != Type::unreachable) {
     shouldBeEqual(curr->left->type,
                   curr->right->type,
                   curr,
@@ -1265,7 +1295,8 @@ void FunctionValidator::visitBinary(Binary* curr) {
     case GtUInt32:
     case GeSInt32:
     case GeUInt32: {
-      shouldBeEqualOrFirstIsUnreachable(curr->left->type, i32, curr, "i32 op");
+      shouldBeEqualOrFirstIsUnreachable(
+        curr->left->type, Type(Type::i32), curr, "i32 op");
       break;
     }
     case AddInt64:
@@ -1293,7 +1324,8 @@ void FunctionValidator::visitBinary(Binary* curr) {
     case GtUInt64:
     case GeSInt64:
     case GeUInt64: {
-      shouldBeEqualOrFirstIsUnreachable(curr->left->type, i64, curr, "i64 op");
+      shouldBeEqualOrFirstIsUnreachable(
+        curr->left->type, Type(Type::i64), curr, "i64 op");
       break;
     }
     case AddFloat32:
@@ -1309,7 +1341,8 @@ void FunctionValidator::visitBinary(Binary* curr) {
     case LeFloat32:
     case GtFloat32:
     case GeFloat32: {
-      shouldBeEqualOrFirstIsUnreachable(curr->left->type, f32, curr, "f32 op");
+      shouldBeEqualOrFirstIsUnreachable(
+        curr->left->type, Type(Type::f32), curr, "f32 op");
       break;
     }
     case AddFloat64:
@@ -1325,7 +1358,8 @@ void FunctionValidator::visitBinary(Binary* curr) {
     case LeFloat64:
     case GtFloat64:
     case GeFloat64: {
-      shouldBeEqualOrFirstIsUnreachable(curr->left->type, f64, curr, "f64 op");
+      shouldBeEqualOrFirstIsUnreachable(
+        curr->left->type, Type(Type::f64), curr, "f64 op");
       break;
     }
     case EqVecI8x16:
@@ -1426,9 +1460,9 @@ void FunctionValidator::visitBinary(Binary* curr) {
     case NarrowUVecI32x4ToVecI16x8:
     case SwizzleVec8x16: {
       shouldBeEqualOrFirstIsUnreachable(
-        curr->left->type, v128, curr, "v128 op");
+        curr->left->type, Type(Type::v128), curr, "v128 op");
       shouldBeEqualOrFirstIsUnreachable(
-        curr->right->type, v128, curr, "v128 op");
+        curr->right->type, Type(Type::v128), curr, "v128 op");
       break;
     }
     case InvalidBinary:
@@ -1441,25 +1475,29 @@ void FunctionValidator::visitBinary(Binary* curr) {
 
 void FunctionValidator::visitUnary(Unary* curr) {
   shouldBeUnequal(curr->value->type,
-                  none,
+                  Type(Type::none),
                   curr,
                   "unaries must not receive a none as their input");
-  if (curr->value->type == unreachable) {
+  if (curr->value->type == Type::unreachable) {
     return; // nothing to check
   }
   switch (curr->op) {
     case ClzInt32:
     case CtzInt32:
     case PopcntInt32: {
-      shouldBeEqual(
-        curr->value->type, i32, curr, "i32 unary value type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i32),
+                    curr,
+                    "i32 unary value type must be correct");
       break;
     }
     case ClzInt64:
     case CtzInt64:
     case PopcntInt64: {
-      shouldBeEqual(
-        curr->value->type, i64, curr, "i64 unary value type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i64),
+                    curr,
+                    "i64 unary value type must be correct");
       break;
     }
     case NegFloat32:
@@ -1469,8 +1507,10 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case TruncFloat32:
     case NearestFloat32:
     case SqrtFloat32: {
-      shouldBeEqual(
-        curr->value->type, f32, curr, "f32 unary value type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f32),
+                    curr,
+                    "f32 unary value type must be correct");
       break;
     }
     case NegFloat64:
@@ -1480,128 +1520,166 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case TruncFloat64:
     case NearestFloat64:
     case SqrtFloat64: {
-      shouldBeEqual(
-        curr->value->type, f64, curr, "f64 unary value type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f64),
+                    curr,
+                    "f64 unary value type must be correct");
       break;
     }
     case EqZInt32: {
-      shouldBeTrue(curr->value->type == i32, curr, "i32.eqz input must be i32");
+      shouldBeTrue(
+        curr->value->type == Type::i32, curr, "i32.eqz input must be i32");
       break;
     }
     case EqZInt64: {
-      shouldBeTrue(curr->value->type == i64, curr, "i64.eqz input must be i64");
+      shouldBeTrue(curr->value->type == Type(Type::i64),
+                   curr,
+                   "i64.eqz input must be i64");
       break;
     }
     case ExtendSInt32:
     case ExtendUInt32:
     case ExtendS8Int32:
     case ExtendS16Int32: {
-      shouldBeEqual(
-        curr->value->type, i32, curr, "extend type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i32),
+                    curr,
+                    "extend type must be correct");
       break;
     }
     case ExtendS8Int64:
     case ExtendS16Int64:
     case ExtendS32Int64: {
-      shouldBeEqual(
-        curr->value->type, i64, curr, "extend type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i64),
+                    curr,
+                    "extend type must be correct");
       break;
     }
     case WrapInt64: {
-      shouldBeEqual(curr->value->type, i64, curr, "wrap type must be correct");
+      shouldBeEqual(
+        curr->value->type, Type(Type::i64), curr, "wrap type must be correct");
       break;
     }
     case TruncSFloat32ToInt32:
     case TruncSFloat32ToInt64:
     case TruncUFloat32ToInt32:
     case TruncUFloat32ToInt64: {
-      shouldBeEqual(curr->value->type, f32, curr, "trunc type must be correct");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f32), curr, "trunc type must be correct");
       break;
     }
     case TruncSatSFloat32ToInt32:
     case TruncSatSFloat32ToInt64:
     case TruncSatUFloat32ToInt32:
     case TruncSatUFloat32ToInt64: {
-      shouldBeEqual(curr->value->type, f32, curr, "trunc type must be correct");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f32), curr, "trunc type must be correct");
       break;
     }
     case TruncSFloat64ToInt32:
     case TruncSFloat64ToInt64:
     case TruncUFloat64ToInt32:
     case TruncUFloat64ToInt64: {
-      shouldBeEqual(curr->value->type, f64, curr, "trunc type must be correct");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f64), curr, "trunc type must be correct");
       break;
     }
     case TruncSatSFloat64ToInt32:
     case TruncSatSFloat64ToInt64:
     case TruncSatUFloat64ToInt32:
     case TruncSatUFloat64ToInt64: {
-      shouldBeEqual(curr->value->type, f64, curr, "trunc type must be correct");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f64), curr, "trunc type must be correct");
       break;
     }
     case ReinterpretFloat32: {
-      shouldBeEqual(
-        curr->value->type, f32, curr, "reinterpret/f32 type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f32),
+                    curr,
+                    "reinterpret/f32 type must be correct");
       break;
     }
     case ReinterpretFloat64: {
-      shouldBeEqual(
-        curr->value->type, f64, curr, "reinterpret/f64 type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f64),
+                    curr,
+                    "reinterpret/f64 type must be correct");
       break;
     }
     case ConvertUInt32ToFloat32:
     case ConvertUInt32ToFloat64:
     case ConvertSInt32ToFloat32:
     case ConvertSInt32ToFloat64: {
-      shouldBeEqual(
-        curr->value->type, i32, curr, "convert type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i32),
+                    curr,
+                    "convert type must be correct");
       break;
     }
     case ConvertUInt64ToFloat32:
     case ConvertUInt64ToFloat64:
     case ConvertSInt64ToFloat32:
     case ConvertSInt64ToFloat64: {
-      shouldBeEqual(
-        curr->value->type, i64, curr, "convert type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i64),
+                    curr,
+                    "convert type must be correct");
       break;
     }
     case PromoteFloat32: {
-      shouldBeEqual(
-        curr->value->type, f32, curr, "promote type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f32),
+                    curr,
+                    "promote type must be correct");
       break;
     }
     case DemoteFloat64: {
-      shouldBeEqual(
-        curr->value->type, f64, curr, "demote type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::f64),
+                    curr,
+                    "demote type must be correct");
       break;
     }
     case ReinterpretInt32: {
-      shouldBeEqual(
-        curr->value->type, i32, curr, "reinterpret/i32 type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i32),
+                    curr,
+                    "reinterpret/i32 type must be correct");
       break;
     }
     case ReinterpretInt64: {
-      shouldBeEqual(
-        curr->value->type, i64, curr, "reinterpret/i64 type must be correct");
+      shouldBeEqual(curr->value->type,
+                    Type(Type::i64),
+                    curr,
+                    "reinterpret/i64 type must be correct");
       break;
     }
     case SplatVecI8x16:
     case SplatVecI16x8:
     case SplatVecI32x4:
-      shouldBeEqual(curr->type, v128, curr, "expected splat to have v128 type");
-      shouldBeEqual(curr->value->type, i32, curr, "expected i32 splat value");
+      shouldBeEqual(
+        curr->type, Type(Type::v128), curr, "expected splat to have v128 type");
+      shouldBeEqual(
+        curr->value->type, Type(Type::i32), curr, "expected i32 splat value");
       break;
     case SplatVecI64x2:
-      shouldBeEqual(curr->type, v128, curr, "expected splat to have v128 type");
-      shouldBeEqual(curr->value->type, i64, curr, "expected i64 splat value");
+      shouldBeEqual(
+        curr->type, Type(Type::v128), curr, "expected splat to have v128 type");
+      shouldBeEqual(
+        curr->value->type, Type(Type::i64), curr, "expected i64 splat value");
       break;
     case SplatVecF32x4:
-      shouldBeEqual(curr->type, v128, curr, "expected splat to have v128 type");
-      shouldBeEqual(curr->value->type, f32, curr, "expected f32 splat value");
+      shouldBeEqual(
+        curr->type, Type(Type::v128), curr, "expected splat to have v128 type");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f32), curr, "expected f32 splat value");
       break;
     case SplatVecF64x2:
-      shouldBeEqual(curr->type, v128, curr, "expected splat to have v128 type");
-      shouldBeEqual(curr->value->type, f64, curr, "expected i64 splat value");
+      shouldBeEqual(
+        curr->type, Type(Type::v128), curr, "expected splat to have v128 type");
+      shouldBeEqual(
+        curr->value->type, Type(Type::f64), curr, "expected f64 splat value");
       break;
     case NotVec128:
     case NegVecI8x16:
@@ -1630,8 +1708,9 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case WidenHighSVecI16x8ToVecI32x4:
     case WidenLowUVecI16x8ToVecI32x4:
     case WidenHighUVecI16x8ToVecI32x4:
-      shouldBeEqual(curr->type, v128, curr, "expected v128 type");
-      shouldBeEqual(curr->value->type, v128, curr, "expected v128 operand");
+      shouldBeEqual(curr->type, Type(Type::v128), curr, "expected v128 type");
+      shouldBeEqual(
+        curr->value->type, Type(Type::v128), curr, "expected v128 operand");
       break;
     case AnyTrueVecI8x16:
     case AllTrueVecI8x16:
@@ -1641,9 +1720,12 @@ void FunctionValidator::visitUnary(Unary* curr) {
     case AllTrueVecI32x4:
     case AnyTrueVecI64x2:
     case AllTrueVecI64x2:
+      shouldBeEqual(curr->type,
+                    Type(Type::i32),
+                    curr,
+                    "expected boolean reduction to have i32 type");
       shouldBeEqual(
-        curr->type, i32, curr, "expected boolean reduction to have i32 type");
-      shouldBeEqual(curr->value->type, v128, curr, "expected v128 operand");
+        curr->value->type, Type(Type::v128), curr, "expected v128 operand");
       break;
     case InvalidUnary:
       WASM_UNREACHABLE("invalid unary op");
@@ -1654,15 +1736,15 @@ void FunctionValidator::visitUnary(Unary* curr) {
 }
 
 void FunctionValidator::visitSelect(Select* curr) {
-  shouldBeUnequal(curr->ifTrue->type, none, curr, "select left must be valid");
   shouldBeUnequal(
-    curr->ifFalse->type, none, curr, "select right must be valid");
-  shouldBeUnequal(curr->type, none, curr, "select type must be valid");
-  shouldBeTrue(curr->condition->type == unreachable ||
-                 curr->condition->type == i32,
+    curr->ifFalse->type, Type(Type::none), curr, "select right must be valid");
+  shouldBeUnequal(
+    curr->type, Type(Type::none), curr, "select type must be valid");
+  shouldBeTrue(curr->condition->type == Type::unreachable ||
+                 curr->condition->type == Type::i32,
                curr,
                "select condition must be valid");
-  if (curr->type != unreachable) {
+  if (curr->type != Type::unreachable) {
     shouldBeTrue(Type::isSubType(curr->ifTrue->type, curr->type),
                  curr,
                  "select's left expression must be subtype of select's type");
@@ -1674,7 +1756,7 @@ void FunctionValidator::visitSelect(Select* curr) {
 
 void FunctionValidator::visitDrop(Drop* curr) {
   shouldBeTrue(curr->value->type.isConcrete() ||
-                 curr->value->type == unreachable,
+                 curr->value->type == Type::unreachable,
                curr,
                "can only drop a valid value");
 }
@@ -1693,7 +1775,7 @@ void FunctionValidator::visitHost(Host* curr) {
                     curr,
                     "memory.grow must have 1 operand");
       shouldBeEqualOrFirstIsUnreachable(curr->operands[0]->type,
-                                        i32,
+                                        Type(Type::i32),
                                         curr,
                                         "memory.grow must have i32 operand");
       break;
@@ -1716,7 +1798,7 @@ void FunctionValidator::visitRefFunc(RefFunc* curr) {
 }
 
 void FunctionValidator::visitTry(Try* curr) {
-  if (curr->type != unreachable) {
+  if (curr->type != Type::unreachable) {
     shouldBeSubTypeOrFirstIsUnreachable(
       curr->body->type,
       curr->type,
@@ -1729,11 +1811,11 @@ void FunctionValidator::visitTry(Try* curr) {
       "try's type does not match catch's body type");
   } else {
     shouldBeEqual(curr->body->type,
-                  unreachable,
+                  Type(Type::unreachable),
                   curr,
                   "unreachable try-catch must have unreachable try body");
     shouldBeEqual(curr->catchBody->type,
-                  unreachable,
+                  Type(Type::unreachable),
                   curr,
                   "unreachable try-catch must have unreachable catch body");
   }
@@ -1743,8 +1825,10 @@ void FunctionValidator::visitThrow(Throw* curr) {
   if (!info.validateGlobally) {
     return;
   }
-  shouldBeEqual(
-    curr->type, unreachable, curr, "throw's type must be unreachable");
+  shouldBeEqual(curr->type,
+                Type(Type::unreachable),
+                curr,
+                "throw's type must be unreachable");
   auto* event = getModule()->getEventOrNull(curr->event);
   if (!shouldBeTrue(!!event, curr, "throw's event must exist")) {
     return;
@@ -1767,8 +1851,10 @@ void FunctionValidator::visitThrow(Throw* curr) {
 }
 
 void FunctionValidator::visitRethrow(Rethrow* curr) {
-  shouldBeEqual(
-    curr->type, unreachable, curr, "rethrow's type must be unreachable");
+  shouldBeEqual(curr->type,
+                Type(Type::unreachable),
+                curr,
+                "rethrow's type must be unreachable");
   shouldBeSubTypeOrFirstIsUnreachable(
     curr->exnref->type,
     Type::exnref,
@@ -1788,13 +1874,13 @@ void FunctionValidator::visitBrOnExn(BrOnExn* curr) {
     Type::exnref,
     curr,
     "br_on_exn's argument must be unreachable or exnref type or its subtype");
-  if (curr->exnref->type == unreachable) {
-    shouldBeTrue(curr->type == unreachable,
+  if (curr->exnref->type == Type::unreachable) {
+    shouldBeTrue(curr->type == Type::unreachable,
                  curr,
                  "If exnref argument's type is unreachable, br_on_exn should "
                  "be unreachable too");
   } else {
-    shouldBeTrue(curr->type == exnref,
+    shouldBeTrue(curr->type == Type::exnref,
                  curr,
                  "br_on_exn's type should be exnref unless its exnref argument "
                  "is unreachable");
@@ -1890,24 +1976,24 @@ void FunctionValidator::validateAlignment(
   }
   shouldBeTrue(align <= bytes, curr, "alignment must not exceed natural");
   switch (type) {
-    case i32:
-    case f32: {
+    case Type::i32:
+    case Type::f32: {
       shouldBeTrue(align <= 4, curr, "alignment must not exceed natural");
       break;
     }
-    case i64:
-    case f64: {
+    case Type::i64:
+    case Type::f64: {
       shouldBeTrue(align <= 8, curr, "alignment must not exceed natural");
       break;
     }
-    case v128:
-    case unreachable:
+    case Type::v128:
+    case Type::unreachable:
       break;
-    case funcref:
-    case anyref:
-    case nullref:
-    case exnref:
-    case none:
+    case Type::funcref:
+    case Type::anyref:
+    case Type::nullref:
+    case Type::exnref:
+    case Type::none:
       WASM_UNREACHABLE("invalid type");
   }
 }
@@ -1970,13 +2056,13 @@ static void validateImports(Module& module, ValidationInfo& info) {
     if (info.validateWeb) {
       for (Type param : curr->sig.params.expand()) {
         info.shouldBeUnequal(param,
-                             i64,
+                             Type(Type::i64),
                              curr->name,
                              "Imported function must not have i64 parameters");
       }
       for (Type result : curr->sig.results.expand()) {
         info.shouldBeUnequal(result,
-                             i64,
+                             Type(Type::i64),
                              curr->name,
                              "Imported function must not have i64 results");
       }
@@ -1998,13 +2084,13 @@ static void validateExports(Module& module, ValidationInfo& info) {
         for (auto param : f->sig.params.expand()) {
           info.shouldBeUnequal(
             param,
-            i64,
+            Type(Type::i64),
             f->name,
             "Exported function must not have i64 parameters");
         }
         for (auto result : f->sig.results.expand()) {
           info.shouldBeUnequal(result,
-                               i64,
+                               Type(Type::i64),
                                f->name,
                                "Exported function must not have i64 results");
         }
@@ -2103,7 +2189,7 @@ static void validateMemory(Module& module, ValidationInfo& info) {
                          "passive segment should not have an offset");
     } else {
       if (!info.shouldBeEqual(segment.offset->type,
-                              i32,
+                              Type(Type::i32),
                               segment.offset,
                               "segment offset should be i32")) {
         continue;
@@ -2136,7 +2222,7 @@ static void validateTable(Module& module, ValidationInfo& info) {
   auto& curr = module.table;
   for (auto& segment : curr.segments) {
     info.shouldBeEqual(segment.offset->type,
-                       i32,
+                       Type(Type::i32),
                        segment.offset,
                        "segment offset should be i32");
     info.shouldBeTrue(checkOffset(segment.offset,
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index 11d203835..a3dc80896 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -220,18 +220,18 @@ struct TypeSeeker : public PostWalker<TypeSeeker> {
 
   void visitBreak(Break* curr) {
     if (curr->name == targetName) {
-      types.push_back(curr->value ? curr->value->type : none);
+      types.push_back(curr->value ? curr->value->type : Type::none);
     }
   }
 
   void visitSwitch(Switch* curr) {
     for (auto name : curr->targets) {
       if (name == targetName) {
-        types.push_back(curr->value ? curr->value->type : none);
+        types.push_back(curr->value ? curr->value->type : Type::none);
       }
     }
     if (curr->default_ == targetName) {
-      types.push_back(curr->value ? curr->value->type : none);
+      types.push_back(curr->value ? curr->value->type : Type::none);
     }
   }
 
@@ -246,7 +246,7 @@ struct TypeSeeker : public PostWalker<TypeSeeker> {
       if (curr->list.size() > 0) {
         types.push_back(curr->list.back()->type);
       } else {
-        types.push_back(none);
+        types.push_back(Type::none);
       }
     } else if (curr->name == targetName) {
       // ignore all breaks til now, they were captured by someone with the same
@@ -271,7 +271,7 @@ struct TypeSeeker : public PostWalker<TypeSeeker> {
 static void handleUnreachable(Block* block,
                               bool breakabilityKnown = false,
                               bool hasBreak = false) {
-  if (block->type == unreachable) {
+  if (block->type == Type::unreachable) {
     return; // nothing to do
   }
   if (block->list.size() == 0) {
@@ -285,14 +285,14 @@ static void handleUnreachable(Block* block,
   }
   // look for an unreachable child
   for (auto* child : block->list) {
-    if (child->type == unreachable) {
+    if (child->type == Type::unreachable) {
       // there is an unreachable child, so we are unreachable, unless we have a
       // break
       if (!breakabilityKnown) {
         hasBreak = BranchUtils::BranchSeeker::has(block, block->name);
       }
       if (!hasBreak) {
-        block->type = unreachable;
+        block->type = Type::unreachable;
       }
       return;
     }
@@ -315,19 +315,19 @@ void Block::finalize() {
         return;
       }
       // if we are unreachable, we are done
-      if (type == unreachable) {
+      if (type == Type::unreachable) {
         return;
       }
       // we may still be unreachable if we have an unreachable
       // child
       for (auto* child : list) {
-        if (child->type == unreachable) {
-          type = unreachable;
+        if (child->type == Type::unreachable) {
+          type = Type::unreachable;
           return;
         }
       }
     } else {
-      type = none;
+      type = Type::none;
     }
     return;
   }
@@ -339,24 +339,24 @@ void Block::finalize() {
 
 void Block::finalize(Type type_) {
   type = type_;
-  if (type == none && list.size() > 0) {
+  if (type == Type::none && list.size() > 0) {
     handleUnreachable(this);
   }
 }
 
 void Block::finalize(Type type_, bool hasBreak) {
   type = type_;
-  if (type == none && list.size() > 0) {
+  if (type == Type::none && list.size() > 0) {
     handleUnreachable(this, true, hasBreak);
   }
 }
 
 void If::finalize(Type type_) {
   type = type_;
-  if (type == none && (condition->type == unreachable ||
-                       (ifFalse && ifTrue->type == unreachable &&
-                        ifFalse->type == unreachable))) {
-    type = unreachable;
+  if (type == Type::none && (condition->type == Type::unreachable ||
+                             (ifFalse && ifTrue->type == Type::unreachable &&
+                              ifFalse->type == Type::unreachable))) {
+    type = Type::unreachable;
   }
 }
 
@@ -371,15 +371,15 @@ void If::finalize() {
   //  (i32.const 20
   // )
   // otherwise, if the condition is unreachable, so is the if
-  if (type == none && condition->type == unreachable) {
-    type = unreachable;
+  if (type == Type::none && condition->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void Loop::finalize(Type type_) {
   type = type_;
-  if (type == none && body->type == unreachable) {
-    type = unreachable;
+  if (type == Type::none && body->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
@@ -387,24 +387,24 @@ void Loop::finalize() { type = body->type; }
 
 void Break::finalize() {
   if (condition) {
-    if (condition->type == unreachable) {
-      type = unreachable;
+    if (condition->type == Type::unreachable) {
+      type = Type::unreachable;
     } else if (value) {
       type = value->type;
     } else {
-      type = none;
+      type = Type::none;
     }
   } else {
-    type = unreachable;
+    type = Type::unreachable;
   }
 }
 
-void Switch::finalize() { type = unreachable; }
+void Switch::finalize() { type = Type::unreachable; }
 
 template<typename T> void handleUnreachableOperands(T* curr) {
   for (auto* child : curr->operands) {
-    if (child->type == unreachable) {
-      curr->type = unreachable;
+    if (child->type == Type::unreachable) {
+      curr->type = Type::unreachable;
       break;
     }
   }
@@ -413,7 +413,7 @@ template<typename T> void handleUnreachableOperands(T* curr) {
 void Call::finalize() {
   handleUnreachableOperands(this);
   if (isReturn) {
-    type = unreachable;
+    type = Type::unreachable;
   }
 }
 
@@ -421,14 +421,14 @@ void CallIndirect::finalize() {
   type = sig.results;
   handleUnreachableOperands(this);
   if (isReturn) {
-    type = unreachable;
+    type = Type::unreachable;
   }
-  if (target->type == unreachable) {
-    type = unreachable;
+  if (target->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
-bool LocalSet::isTee() const { return type != none; }
+bool LocalSet::isTee() const { return type != Type::none; }
 
 // Changes to local.tee. The type of the local should be given.
 void LocalSet::makeTee(Type type_) {
@@ -438,62 +438,63 @@ void LocalSet::makeTee(Type type_) {
 
 // Changes to local.set.
 void LocalSet::makeSet() {
-  type = none;
+  type = Type::none;
   finalize(); // type may need to be unreachable
 }
 
 void LocalSet::finalize() {
-  if (value->type == unreachable) {
-    type = unreachable;
+  if (value->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void GlobalSet::finalize() {
-  if (value->type == unreachable) {
-    type = unreachable;
+  if (value->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void Load::finalize() {
-  if (ptr->type == unreachable) {
-    type = unreachable;
+  if (ptr->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void Store::finalize() {
-  assert(valueType != none); // must be set
-  if (ptr->type == unreachable || value->type == unreachable) {
-    type = unreachable;
+  assert(valueType != Type::none); // must be set
+  if (ptr->type == Type::unreachable || value->type == Type::unreachable) {
+    type = Type::unreachable;
   } else {
-    type = none;
+    type = Type::none;
   }
 }
 
 void AtomicRMW::finalize() {
-  if (ptr->type == unreachable || value->type == unreachable) {
-    type = unreachable;
+  if (ptr->type == Type::unreachable || value->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void AtomicCmpxchg::finalize() {
-  if (ptr->type == unreachable || expected->type == unreachable ||
-      replacement->type == unreachable) {
-    type = unreachable;
+  if (ptr->type == Type::unreachable || expected->type == Type::unreachable ||
+      replacement->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void AtomicWait::finalize() {
-  type = i32;
-  if (ptr->type == unreachable || expected->type == unreachable ||
-      timeout->type == unreachable) {
-    type = unreachable;
+  type = Type::i32;
+  if (ptr->type == Type::unreachable || expected->type == Type::unreachable ||
+      timeout->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void AtomicNotify::finalize() {
-  type = i32;
-  if (ptr->type == unreachable || notifyCount->type == unreachable) {
-    type = unreachable;
+  type = Type::i32;
+  if (ptr->type == Type::unreachable ||
+      notifyCount->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
@@ -505,92 +506,92 @@ void SIMDExtract::finalize() {
     case ExtractLaneSVecI16x8:
     case ExtractLaneUVecI16x8:
     case ExtractLaneVecI32x4:
-      type = i32;
+      type = Type::i32;
       break;
     case ExtractLaneVecI64x2:
-      type = i64;
+      type = Type::i64;
       break;
     case ExtractLaneVecF32x4:
-      type = f32;
+      type = Type::f32;
       break;
     case ExtractLaneVecF64x2:
-      type = f64;
+      type = Type::f64;
       break;
     default:
       WASM_UNREACHABLE("unexpected op");
   }
-  if (vec->type == unreachable) {
-    type = unreachable;
+  if (vec->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void SIMDReplace::finalize() {
   assert(vec && value);
-  type = v128;
-  if (vec->type == unreachable || value->type == unreachable) {
-    type = unreachable;
+  type = Type::v128;
+  if (vec->type == Type::unreachable || value->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void SIMDShuffle::finalize() {
   assert(left && right);
-  type = v128;
-  if (left->type == unreachable || right->type == unreachable) {
-    type = unreachable;
+  type = Type::v128;
+  if (left->type == Type::unreachable || right->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void SIMDTernary::finalize() {
   assert(a && b && c);
-  type = v128;
-  if (a->type == unreachable || b->type == unreachable ||
-      c->type == unreachable) {
-    type = unreachable;
+  type = Type::v128;
+  if (a->type == Type::unreachable || b->type == Type::unreachable ||
+      c->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void MemoryInit::finalize() {
   assert(dest && offset && size);
-  type = none;
-  if (dest->type == unreachable || offset->type == unreachable ||
-      size->type == unreachable) {
-    type = unreachable;
+  type = Type::none;
+  if (dest->type == Type::unreachable || offset->type == Type::unreachable ||
+      size->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
-void DataDrop::finalize() { type = none; }
+void DataDrop::finalize() { type = Type::none; }
 
 void MemoryCopy::finalize() {
   assert(dest && source && size);
-  type = none;
-  if (dest->type == unreachable || source->type == unreachable ||
-      size->type == unreachable) {
-    type = unreachable;
+  type = Type::none;
+  if (dest->type == Type::unreachable || source->type == Type::unreachable ||
+      size->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void MemoryFill::finalize() {
   assert(dest && value && size);
-  type = none;
-  if (dest->type == unreachable || value->type == unreachable ||
-      size->type == unreachable) {
-    type = unreachable;
+  type = Type::none;
+  if (dest->type == Type::unreachable || value->type == Type::unreachable ||
+      size->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void SIMDShift::finalize() {
   assert(vec && shift);
-  type = v128;
-  if (vec->type == unreachable || shift->type == unreachable) {
-    type = unreachable;
+  type = Type::v128;
+  if (vec->type == Type::unreachable || shift->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
 void SIMDLoad::finalize() {
   assert(ptr);
-  type = v128;
-  if (ptr->type == unreachable) {
-    type = unreachable;
+  type = Type::v128;
+  if (ptr->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
@@ -625,8 +626,8 @@ void Const::finalize() { type = value.type; }
 bool Unary::isRelational() { return op == EqZInt32 || op == EqZInt64; }
 
 void Unary::finalize() {
-  if (value->type == unreachable) {
-    type = unreachable;
+  if (value->type == Type::unreachable) {
+    type = Type::unreachable;
     return;
   }
   switch (op) {
@@ -654,27 +655,27 @@ void Unary::finalize() {
       break;
     case EqZInt32:
     case EqZInt64:
-      type = i32;
+      type = Type::i32;
       break;
     case ExtendS8Int32:
     case ExtendS16Int32:
-      type = i32;
+      type = Type::i32;
       break;
     case ExtendSInt32:
     case ExtendUInt32:
     case ExtendS8Int64:
     case ExtendS16Int64:
     case ExtendS32Int64:
-      type = i64;
+      type = Type::i64;
       break;
     case WrapInt64:
-      type = i32;
+      type = Type::i32;
       break;
     case PromoteFloat32:
-      type = f64;
+      type = Type::f64;
       break;
     case DemoteFloat64:
-      type = f32;
+      type = Type::f32;
       break;
     case TruncSFloat32ToInt32:
     case TruncUFloat32ToInt32:
@@ -685,7 +686,7 @@ void Unary::finalize() {
     case TruncSatSFloat64ToInt32:
     case TruncSatUFloat64ToInt32:
     case ReinterpretFloat32:
-      type = i32;
+      type = Type::i32;
       break;
     case TruncSFloat32ToInt64:
     case TruncUFloat32ToInt64:
@@ -696,21 +697,21 @@ void Unary::finalize() {
     case TruncSatSFloat64ToInt64:
     case TruncSatUFloat64ToInt64:
     case ReinterpretFloat64:
-      type = i64;
+      type = Type::i64;
       break;
     case ReinterpretInt32:
     case ConvertSInt32ToFloat32:
     case ConvertUInt32ToFloat32:
     case ConvertSInt64ToFloat32:
     case ConvertUInt64ToFloat32:
-      type = f32;
+      type = Type::f32;
       break;
     case ReinterpretInt64:
     case ConvertSInt32ToFloat64:
     case ConvertUInt32ToFloat64:
     case ConvertSInt64ToFloat64:
     case ConvertUInt64ToFloat64:
-      type = f64;
+      type = Type::f64;
       break;
     case SplatVecI8x16:
     case SplatVecI16x8:
@@ -745,7 +746,7 @@ void Unary::finalize() {
     case WidenHighSVecI16x8ToVecI32x4:
     case WidenLowUVecI16x8ToVecI32x4:
     case WidenHighUVecI16x8ToVecI32x4:
-      type = v128;
+      type = Type::v128;
       break;
     case AnyTrueVecI8x16:
     case AllTrueVecI8x16:
@@ -755,7 +756,7 @@ void Unary::finalize() {
     case AllTrueVecI32x4:
     case AnyTrueVecI64x2:
     case AllTrueVecI64x2:
-      type = i32;
+      type = Type::i32;
       break;
 
     case InvalidUnary:
@@ -805,10 +806,10 @@ bool Binary::isRelational() {
 
 void Binary::finalize() {
   assert(left && right);
-  if (left->type == unreachable || right->type == unreachable) {
-    type = unreachable;
+  if (left->type == Type::unreachable || right->type == Type::unreachable) {
+    type = Type::unreachable;
   } else if (isRelational()) {
-    type = i32;
+    type = Type::i32;
   } else {
     type = left->type;
   }
@@ -818,34 +819,34 @@ void Select::finalize(Type type_) { type = type_; }
 
 void Select::finalize() {
   assert(ifTrue && ifFalse);
-  if (ifTrue->type == unreachable || ifFalse->type == unreachable ||
-      condition->type == unreachable) {
-    type = unreachable;
+  if (ifTrue->type == Type::unreachable || ifFalse->type == Type::unreachable ||
+      condition->type == Type::unreachable) {
+    type = Type::unreachable;
   } else {
     type = Type::getLeastUpperBound(ifTrue->type, ifFalse->type);
   }
 }
 
 void Drop::finalize() {
-  if (value->type == unreachable) {
-    type = unreachable;
+  if (value->type == Type::unreachable) {
+    type = Type::unreachable;
   } else {
-    type = none;
+    type = Type::none;
   }
 }
 
 void Host::finalize() {
   switch (op) {
     case MemorySize: {
-      type = i32;
+      type = Type::i32;
       break;
     }
     case MemoryGrow: {
       // if the single operand is not reachable, so are we
-      if (operands[0]->type == unreachable) {
-        type = unreachable;
+      if (operands[0]->type == Type::unreachable) {
+        type = Type::unreachable;
       } else {
-        type = i32;
+        type = Type::i32;
       }
       break;
     }
@@ -870,29 +871,29 @@ void Try::finalize() {
 
 void Try::finalize(Type type_) {
   type = type_;
-  if (type == none && body->type == unreachable &&
-      catchBody->type == unreachable) {
-    type = unreachable;
+  if (type == Type::none && body->type == Type::unreachable &&
+      catchBody->type == Type::unreachable) {
+    type = Type::unreachable;
   }
 }
 
-void Throw::finalize() { type = unreachable; }
+void Throw::finalize() { type = Type::unreachable; }
 
-void Rethrow::finalize() { type = unreachable; }
+void Rethrow::finalize() { type = Type::unreachable; }
 
 void BrOnExn::finalize() {
-  if (exnref->type == unreachable) {
-    type = unreachable;
+  if (exnref->type == Type::unreachable) {
+    type = Type::unreachable;
   } else {
     type = Type::exnref;
   }
 }
 
 void Push::finalize() {
-  if (value->type == unreachable) {
-    type = unreachable;
+  if (value->type == Type::unreachable) {
+    type = Type::unreachable;
   } else {
-    type = none;
+    type = Type::none;
   }
 }
 
diff --git a/src/wasm2js.h b/src/wasm2js.h
index 9f6c19338..609373cca 100644
--- a/src/wasm2js.h
+++ b/src/wasm2js.h
@@ -415,7 +415,7 @@ Ref Wasm2JSBuilder::processWasm(Module* wasm, Name funcName) {
                            Signature(Type::none, Type::i32),
                            {},
                            builder.makeReturn(builder.makeGlobalGet(
-                             INT64_TO_32_HIGH_BITS, i32)))));
+                             INT64_TO_32_HIGH_BITS, Type::i32)))));
     auto e = new Export();
     e->name = WASM_FETCH_HIGH_BITS;
     e->value = WASM_FETCH_HIGH_BITS;
@@ -517,7 +517,7 @@ void Wasm2JSBuilder::addGlobalImport(Ref ast, Global* import) {
   Ref module = ValueBuilder::makeName(ENV);
   Ref value =
     ValueBuilder::makeDot(module, fromName(import->base, NameScope::Top));
-  if (import->type == i32) {
+  if (import->type == Type::i32) {
     value = makeAsmCoercion(value, ASM_INT);
   }
   ValueBuilder::appendToVar(
@@ -677,10 +677,10 @@ Ref Wasm2JSBuilder::processFunction(Module* m,
   Names::ensureNames(func);
   Ref ret = ValueBuilder::makeFunction(fromName(func->name, NameScope::Top));
   frees.clear();
-  frees.resize(std::max(i32, std::max(f32, f64)) + 1);
+  frees.resize(std::max(Type::i32, std::max(Type::f32, Type::f64)) + 1);
   temps.clear();
-  temps.resize(std::max(i32, std::max(f32, f64)) + 1);
-  temps[i32] = temps[f32] = temps[f64] = 0;
+  temps.resize(std::max(Type::i32, std::max(Type::f32, Type::f64)) + 1);
+  temps[Type::i32] = temps[Type::f32] = temps[Type::f64] = 0;
   // arguments
   bool needCoercions = options.optimizeLevel == 0 || standaloneFunction ||
                        functionsCallableFromOutside.count(func->name);
@@ -711,9 +711,9 @@ Ref Wasm2JSBuilder::processFunction(Module* m,
     ret[3]->splice(theVarIndex, 1);
   }
   // checks: all temp vars should be free at the end
-  assert(frees[i32].size() == temps[i32]);
-  assert(frees[f32].size() == temps[f32]);
-  assert(frees[f64].size() == temps[f64]);
+  assert(frees[Type::i32].size() == temps[Type::i32]);
+  assert(frees[Type::f32].size() == temps[Type::f32]);
+  assert(frees[Type::f64].size() == temps[Type::f64]);
   return ret;
 }
 
@@ -980,8 +980,8 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       continueLabels.insert(asmLabel);
       Ref body = visit(curr->body, result);
       // if we can reach the end of the block, we must leave the while (1) loop
-      if (curr->body->type != unreachable) {
-        assert(curr->body->type == none); // flat IR
+      if (curr->body->type != Type::Type::unreachable) {
+        assert(curr->body->type == Type::Type::none); // flat IR
         body = blockify(body);
         flattenAppend(
           body, ValueBuilder::makeBreak(fromName(asmLabel, NameScope::Label)));
@@ -1045,7 +1045,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
         for (auto* c : code) {
           ValueBuilder::appendCodeToSwitch(
             theSwitch, blockify(visit(c, NO_RESULT)), false);
-          hoistedEndsWithUnreachable = c->type == unreachable;
+          hoistedEndsWithUnreachable = c->type == Type::Type::unreachable;
         }
       }
       // After the hoisted cases, if any remain we must make sure not to
@@ -1138,7 +1138,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       }
       if (mustReorder) {
         Ref ret;
-        ScopedTemp idx(i32, parent, func);
+        ScopedTemp idx(Type::i32, parent, func);
         std::vector<ScopedTemp*> temps; // TODO: utility class, with destructor?
         for (auto* operand : curr->operands) {
           temps.push_back(new ScopedTemp(operand->type, parent, func));
@@ -1211,7 +1211,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       Ref ptr = makePointer(curr->ptr, curr->offset);
       Ref ret;
       switch (curr->type) {
-        case i32: {
+        case Type::i32: {
           switch (curr->bytes) {
             case 1:
               ret = ValueBuilder::makeSub(
@@ -1239,11 +1239,11 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
           }
           break;
         }
-        case f32:
+        case Type::f32:
           ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF32),
                                       ValueBuilder::makePtrShift(ptr, 2));
           break;
-        case f64:
+        case Type::f64:
           ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF64),
                                       ValueBuilder::makePtrShift(ptr, 3));
           break;
@@ -1265,7 +1265,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
 
     Ref visitStore(Store* curr) {
       if (module->memory.initial < module->memory.max &&
-          curr->type != unreachable) {
+          curr->type != Type::Type::unreachable) {
         // In JS, if memory grows then it is dangerous to write
         //  HEAP[f()] = ..
         // or
@@ -1281,13 +1281,13 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
             !FindAll<Host>(curr->ptr).list.empty() ||
             !FindAll<Host>(curr->value).list.empty()) {
           Ref ret;
-          ScopedTemp ptr(i32, parent, func);
+          ScopedTemp ptr(Type::i32, parent, func);
           sequenceAppend(ret, visitAndAssign(curr->ptr, ptr));
           ScopedTemp value(curr->value->type, parent, func);
           sequenceAppend(ret, visitAndAssign(curr->value, value));
           LocalGet getPtr;
           getPtr.index = func->getLocalIndex(ptr.getName());
-          getPtr.type = i32;
+          getPtr.type = Type::i32;
           LocalGet getValue;
           getValue.index = func->getLocalIndex(value.getName());
           getValue.type = curr->value->type;
@@ -1307,7 +1307,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       Ref value = visit(curr->value, EXPRESSION_RESULT);
       Ref ret;
       switch (curr->valueType) {
-        case i32: {
+        case Type::i32: {
           switch (curr->bytes) {
             case 1:
               ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAP8),
@@ -1326,11 +1326,11 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
           }
           break;
         }
-        case f32:
+        case Type::f32:
           ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF32),
                                       ValueBuilder::makePtrShift(ptr, 2));
           break;
-        case f64:
+        case Type::f64:
           ret = ValueBuilder::makeSub(ValueBuilder::makeName(HEAPF64),
                                       ValueBuilder::makePtrShift(ptr, 3));
           break;
@@ -1347,12 +1347,12 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
 
     Ref visitConst(Const* curr) {
       switch (curr->type) {
-        case i32:
+        case Type::i32:
           return ValueBuilder::makeInt(curr->value.geti32());
         // An i64 argument translates to two actual arguments to asm.js
         // functions, so we do a bit of a hack here to get our one `Ref` to look
         // like two function arguments.
-        case i64: {
+        case Type::i64: {
           auto lo = (unsigned)curr->value.geti64();
           auto hi = (unsigned)(curr->value.geti64() >> 32);
           std::ostringstream out;
@@ -1361,15 +1361,15 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
           IString name(os.c_str(), false);
           return ValueBuilder::makeName(name);
         }
-        case f32: {
+        case Type::f32: {
           Ref ret = ValueBuilder::makeCall(MATH_FROUND);
           Const fake(allocator);
           fake.value = Literal(double(curr->value.getf32()));
-          fake.type = f64;
+          fake.type = Type::f64;
           ret[2]->push_back(visitConst(&fake));
           return ret;
         }
-        case f64: {
+        case Type::f64: {
           double d = curr->value.getf64();
           if (d == 0 && std::signbit(d)) { // negative zero
             return ValueBuilder::makeUnary(
@@ -1387,7 +1387,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
     Ref visitUnary(Unary* curr) {
       // normal unary
       switch (curr->type) {
-        case i32: {
+        case Type::i32: {
           switch (curr->op) {
             case ClzInt32: {
               return ValueBuilder::makeCall(
@@ -1446,8 +1446,8 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
             }
           }
         }
-        case f32:
-        case f64: {
+        case Type::f32:
+        case Type::f64: {
           Ref ret;
           switch (curr->op) {
             case NegFloat32:
@@ -1528,7 +1528,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
             default:
               WASM_UNREACHABLE("unhandled unary float operator");
           }
-          if (curr->type == f32) { // doubles need much less coercing
+          if (curr->type == Type::f32) { // doubles need much less coercing
             return makeAsmCoercion(ret, ASM_FLOAT);
           }
           return ret;
@@ -1546,7 +1546,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       Ref right = visit(curr->right, EXPRESSION_RESULT);
       Ref ret;
       switch (curr->type) {
-        case i32: {
+        case Type::i32: {
           switch (curr->op) {
             case AddInt32:
               ret = ValueBuilder::makeBinary(left, PLUS, right);
@@ -1555,7 +1555,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
               ret = ValueBuilder::makeBinary(left, MINUS, right);
               break;
             case MulInt32: {
-              if (curr->type == i32) {
+              if (curr->type == Type::i32) {
                 // TODO: when one operand is a small int, emit a multiply
                 return ValueBuilder::makeCall(MATH_IMUL, left, right);
               } else {
@@ -1668,8 +1668,8 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
           }
           break;
         }
-        case f32:
-        case f64:
+        case Type::f32:
+        case Type::f64:
           switch (curr->op) {
             case AddFloat32:
             case AddFloat64:
@@ -1702,7 +1702,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
                         << std::endl;
               abort();
           }
-          if (curr->type == f32) {
+          if (curr->type == Type::f32) {
             return makeAsmCoercion(ret, ASM_FLOAT);
           }
           return ret;
@@ -1729,7 +1729,7 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
       if (useLocals) {
         ScopedTemp tempIfTrue(curr->type, parent, func),
           tempIfFalse(curr->type, parent, func),
-          tempCondition(i32, parent, func);
+          tempCondition(Type::i32, parent, func);
         Ref ifTrue = visit(curr->ifTrue, EXPRESSION_RESULT);
         Ref ifFalse = visit(curr->ifFalse, EXPRESSION_RESULT);
         Ref condition = visit(curr->condition, EXPRESSION_RESULT);