2 files changed, 20 insertions, 3 deletions
diff --git a/src/ir/properties.cpp b/src/ir/properties.cpp
index 4ade8aa10..b564b3bf1 100644
--- a/src/ir/properties.cpp
+++ b/src/ir/properties.cpp
@@ -36,6 +36,8 @@ bool isGenerative(Expression* curr, FeatureSet features) {
   return scanner.generative;
 }
 
+// Checks an expression in a shallow manner (i.e., does not check children) as
+// to whether it is valid in a wasm constant expression.
 static bool isValidInConstantExpression(Module& wasm, Expression* expr) {
   if (isSingleConstantExpression(expr) || expr->is<StructNew>() ||
       expr->is<ArrayNew>() || expr->is<ArrayNewFixed>() || expr->is<I31New>() ||
@@ -43,6 +45,12 @@ static bool isValidInConstantExpression(Module& wasm, Expression* expr) {
     return true;
   }
 
+  if (auto* refAs = expr->dynCast<RefAs>()) {
+    if (refAs->op == ExternExternalize || refAs->op == ExternInternalize) {
+      return true;
+    }
+  }
+
   if (auto* get = expr->dynCast<GlobalGet>()) {
     auto* g = wasm.getGlobalOrNull(get->name);
     // This is called from the validator, so we have to handle non-existent
diff --git a/src/ir/properties.h b/src/ir/properties.h
index 13eea6ba2..d47cf774b 100644
--- a/src/ir/properties.h
+++ b/src/ir/properties.h
@@ -82,10 +82,13 @@ inline bool isNamedControlFlow(Expression* curr) {
 // runtime will be equal as well. TODO: combine this with
 // isValidInConstantExpression or find better names(#4845)
 inline bool isSingleConstantExpression(const Expression* curr) {
+  if (auto* refAs = curr->dynCast<RefAs>()) {
+    if (refAs->op == ExternExternalize || refAs->op == ExternInternalize) {
+      return isSingleConstantExpression(refAs->value);
+    }
+  }
   return curr->is<Const>() || curr->is<RefNull>() || curr->is<RefFunc>() ||
-         curr->is<StringConst>() ||
-         (curr->is<RefAs>() && (curr->cast<RefAs>()->op == ExternExternalize ||
-                                curr->cast<RefAs>()->op == ExternInternalize));
+         curr->is<StringConst>();
 }
 
 inline bool isConstantExpression(const Expression* curr) {
@@ -120,6 +123,12 @@ inline Literal getLiteral(const Expression* curr) {
     }
   } else if (auto* s = curr->dynCast<StringConst>()) {
     return Literal(s->string.toString());
+  } else if (auto* r = curr->dynCast<RefAs>()) {
+    if (r->op == ExternExternalize) {
+      return getLiteral(r->value).externalize();
+    } else if (r->op == ExternInternalize) {
+      return getLiteral(r->value).internalize();
+    }
   }
   WASM_UNREACHABLE("non-constant expression");
 }