Fix some multi-value bugs; run spec tests

Running the multi-value spec tests found a few bugs:

* DropKeep needs to copy the kept values backward when the regions
  overlap.

* Type names need to be resolved to indexes in block declarations
  (e.g. `block (type $foo)`)

* `if` without an `else` is valid, it just behaves as though the `else`
  is empty, which will pass the params through as results.

* When validating function signatures, we need to also check block
  declaration signatures.

* Split `ResolveFuncType` into two functions:
  `ResolveFuncTypeWithEmptySignature` and
  `ResolveImplicitlyDefinedFunctionType`.

* When resolving implicitly defined function types, we only create an
  implicit function type when the type is not inlinable; i.e. only for
  block/loop/if with 0 or 1 result values and no params.

* Change `update-spec-tests` to include the `multi-value` proposal repo
  from the testsuite.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/validator.cc b/src/validator.cc
index a418e309..27bf2422 100644
--- a/src/validator.cc
+++ b/src/validator.cc
@@ -1398,11 +1398,41 @@ class Validator::CheckFuncSignatureExprVisitorDelegate
   explicit CheckFuncSignatureExprVisitorDelegate(Validator* validator)
       : validator_(validator) {}
 
+  Result BeginBlockExpr(BlockExpr* expr) override {
+    validator_->CheckBlockDeclaration(&expr->loc, Opcode::Block,
+                                      &expr->block.decl);
+    return Result::Ok;
+  }
+
   Result OnCallIndirectExpr(CallIndirectExpr* expr) override {
     validator_->CheckFuncSignature(&expr->loc, expr->decl);
     return Result::Ok;
   }
 
+  Result BeginIfExpr(IfExpr* expr) override {
+    validator_->CheckBlockDeclaration(&expr->loc, Opcode::If,
+                                      &expr->true_.decl);
+    return Result::Ok;
+  }
+
+  Result BeginIfExceptExpr(IfExceptExpr* expr) override {
+    validator_->CheckBlockDeclaration(&expr->loc, Opcode::IfExcept,
+                                      &expr->true_.decl);
+    return Result::Ok;
+  }
+
+  Result BeginLoopExpr(LoopExpr* expr) override {
+    validator_->CheckBlockDeclaration(&expr->loc, Opcode::Loop,
+                                      &expr->block.decl);
+    return Result::Ok;
+  }
+
+  Result BeginTryExpr(TryExpr* expr) override {
+    validator_->CheckBlockDeclaration(&expr->loc, Opcode::Try,
+                                      &expr->block.decl);
+    return Result::Ok;
+  }
+
  private:
   Validator* validator_;
 };