3 files changed, 24 insertions, 21 deletions
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 1de5e4bd1..4e5db69b1 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -3776,12 +3776,13 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       visitMemoryGrow(grow);
       break;
     }
-    case BinaryConsts::CallRef:
+    case BinaryConsts::CallRefUnannotated:
       visitCallRef((curr = allocator.alloc<CallRef>())->cast<CallRef>());
       break;
+    case BinaryConsts::CallRef:
     case BinaryConsts::RetCallRef: {
       auto call = allocator.alloc<CallRef>();
-      call->isReturn = true;
+      call->isReturn = code == BinaryConsts::RetCallRef;
       curr = call;
       visitCallRef(call, getTypeByIndex(getU32LEB()));
       break;
@@ -6810,11 +6811,7 @@ void WasmBinaryBuilder::visitCallRef(CallRef* curr,
   for (size_t i = 0; i < num; i++) {
     curr->operands[num - i - 1] = popNonVoidExpression();
   }
-  if (maybeType) {
-    curr->finalize();
-  } else {
-    curr->finalize(sig.results);
-  }
+  curr->finalize(sig.results);
 }
 
 bool WasmBinaryBuilder::maybeVisitI31New(Expression*& out, uint32_t code) {
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index cf4824323..6de8744a6 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -2831,22 +2831,31 @@ Expression* SExpressionWasmBuilder::makeTupleExtract(Element& s) {
 
 Expression* SExpressionWasmBuilder::makeCallRef(Element& s, bool isReturn) {
   Index operandsStart = 1;
-  HeapType sigType;
-  if (isReturn) {
+  std::optional<HeapType> sigType;
+  try {
     sigType = parseHeapType(*s[1]);
     operandsStart = 2;
+  } catch (ParseException& p) {
+    // The type annotation is required for return_call_ref but temporarily
+    // optional for call_ref.
+    if (isReturn) {
+      throw;
+    }
   }
   std::vector<Expression*> operands;
   parseOperands(s, operandsStart, s.size() - 1, operands);
   auto* target = parseExpression(s[s.size() - 1]);
 
-  if (isReturn) {
-    if (!sigType.isSignature()) {
+  if (sigType) {
+    if (!sigType->isSignature()) {
       throw ParseException(
-        "return_call_ref type annotation should be a signature", s.line, s.col);
+        std::string(isReturn ? "return_call_ref" : "call_ref") +
+          " type annotation should be a signature",
+        s.line,
+        s.col);
     }
     return Builder(wasm).makeCallRef(
-      target, operands, sigType.getSignature().results, isReturn);
+      target, operands, sigType->getSignature().results, isReturn);
   }
   return ValidatingBuilder(wasm, s.line, s.col)
     .validateAndMakeCallRef(target, operands, isReturn);
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index 243b2810b..71bc98928 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -2013,14 +2013,11 @@ void BinaryInstWriter::visitI31Get(I31Get* curr) {
 }
 
 void BinaryInstWriter::visitCallRef(CallRef* curr) {
-  if (curr->isReturn) {
-    assert(curr->target->type != Type::unreachable);
-    // TODO: `emitUnreachable` if target has bottom type.
-    o << int8_t(BinaryConsts::RetCallRef);
-    parent.writeIndexedHeapType(curr->target->type.getHeapType());
-    return;
-  }
-  o << int8_t(BinaryConsts::CallRef);
+  assert(curr->target->type != Type::unreachable);
+  // TODO: `emitUnreachable` if target has bottom type.
+  o << int8_t(curr->isReturn ? BinaryConsts::RetCallRef
+                             : BinaryConsts::CallRef);
+  parent.writeIndexedHeapType(curr->target->type.getHeapType());
 }
 
 void BinaryInstWriter::visitRefTest(RefTest* curr) {