--- a/js/src/wasm/WasmModule.cpp
+++ b/js/src/wasm/WasmModule.cpp
@@ -1170,20 +1170,22 @@ static bool CreateExportObject(JSContext
 
 #ifdef ENABLE_WASM_GC
 static bool MakeStructField(JSContext* cx, const ValType& v, bool isMutable,
                             const char* format, uint32_t fieldNo,
                             AutoIdVector* ids, AutoValueVector* fieldTypeObjs,
                             Vector<StructFieldProps>* fieldProps) {
   char buf[20];
   sprintf(buf, format, fieldNo);
-  RootedString str(cx, JS_AtomizeAndPinString(cx, buf));
-  if (!str) {
+
+  JSAtom* atom = Atomize(cx, buf, strlen(buf));
+  if (!atom) {
     return false;
   }
+  RootedId id(cx, AtomToId(atom));
 
   StructFieldProps props;
   props.isMutable = isMutable;
 
   Rooted<TypeDescr*> t(cx);
   switch (v.code()) {
     case ValType::I32:
       t = GlobalObject::getOrCreateScalarTypeDescr(cx, cx->global(),
@@ -1213,17 +1215,17 @@ static bool MakeStructField(JSContext* c
       t = GlobalObject::getOrCreateReferenceTypeDescr(
           cx, cx->global(), ReferenceType::TYPE_WASM_ANYREF);
       break;
     default:
       MOZ_CRASH("Bad field type");
   }
   MOZ_ASSERT(t != nullptr);
 
-  if (!ids->append(INTERNED_STRING_TO_JSID(cx, str))) {
+  if (!ids->append(id)) {
     return false;
   }
 
   if (!fieldTypeObjs->append(ObjectValue(*t))) {
     return false;
   }
 
   if (!fieldProps->append(props)) {