5 files changed, 21 insertions, 11 deletions
diff --git a/src/wasm/literal.cpp b/src/wasm/literal.cpp
index f13ea504f..20b6b7234 100644
--- a/src/wasm/literal.cpp
+++ b/src/wasm/literal.cpp
@@ -57,7 +57,8 @@ Literal::Literal(Type type) : type(type) {
     return;
   }
 
-  if (type.isRef() && type.getHeapType() == HeapType::i31) {
+  if (type.isRef() && type.getHeapType().isBasic() &&
+      type.getHeapType().getBasic(Unshared) == HeapType::i31) {
     assert(type.isNonNullable());
     i32 = 0;
     return;
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 78470324c..74d74f473 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -7244,13 +7244,19 @@ void WasmBinaryReader::visitCallRef(CallRef* curr) {
 }
 
 bool WasmBinaryReader::maybeVisitRefI31(Expression*& out, uint32_t code) {
-  if (code != BinaryConsts::RefI31) {
-    return false;
+  Shareability share;
+  switch (code) {
+    case BinaryConsts::RefI31:
+      share = Unshared;
+      break;
+    case BinaryConsts::RefI31Shared:
+      share = Shared;
+      break;
+    default:
+      return false;
   }
-  auto* curr = allocator.alloc<RefI31>();
-  curr->value = popNonVoidExpression();
-  curr->finalize();
-  out = curr;
+  auto* value = popNonVoidExpression();
+  out = Builder(wasm).makeRefI31(value, share);
   return true;
 }
 
diff --git a/src/wasm/wasm-ir-builder.cpp b/src/wasm/wasm-ir-builder.cpp
index 63f5df4c0..3db6238c4 100644
--- a/src/wasm/wasm-ir-builder.cpp
+++ b/src/wasm/wasm-ir-builder.cpp
@@ -1605,10 +1605,10 @@ Result<> IRBuilder::makeTupleDrop(uint32_t arity) {
   return Ok{};
 }
 
-Result<> IRBuilder::makeRefI31() {
+Result<> IRBuilder::makeRefI31(Shareability share) {
   RefI31 curr;
   CHECK_ERR(visitRefI31(&curr));
-  push(builder.makeRefI31(curr.value));
+  push(builder.makeRefI31(curr.value, share));
   return Ok{};
 }
 
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index 40a50706a..cd0a9928e 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -2114,7 +2114,9 @@ void BinaryInstWriter::visitTupleExtract(TupleExtract* curr) {
 }
 
 void BinaryInstWriter::visitRefI31(RefI31* curr) {
-  o << int8_t(BinaryConsts::GCPrefix) << U32LEB(BinaryConsts::RefI31);
+  o << int8_t(BinaryConsts::GCPrefix)
+    << U32LEB(curr->type.getHeapType().isShared() ? BinaryConsts::RefI31Shared
+                                                  : BinaryConsts::RefI31);
 }
 
 void BinaryInstWriter::visitI31Get(I31Get* curr) {
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index 8a2b4755c..c4f02128e 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -964,7 +964,8 @@ void RefI31::finalize() {
   if (value->type == Type::unreachable) {
     type = Type::unreachable;
   } else {
-    type = Type(HeapType::i31, NonNullable);
+    assert(type.isRef() && type.getHeapType().isBasic() &&
+           type.getHeapType().getBasic(Unshared) == HeapType::i31);
   }
 }