Fix issues with ref.cast_nop (#5473)

It did not have proper annotation for the safety field, and also
it could not handle basic heap types.

Author: kripken

src/wasm-delegations-fields.def

@@ -620,6 +620,7 @@ switch (DELEGATE_ID) {
   }
   case Expression::Id::RefCastId: {
     DELEGATE_START(RefCast);
+    DELEGATE_FIELD_INT(RefCast, safety);
     DELEGATE_FIELD_CHILD(RefCast, ref);
     DELEGATE_END(RefCast);
     break;

src/wasm/wasm-binary.cpp

@@ -6935,8 +6935,7 @@ void WasmBinaryBuilder::visitRefAsCast(RefCast* curr, uint32_t code) {
 bool WasmBinaryBuilder::maybeVisitRefCast(Expression*& out, uint32_t code) {
   if (code == BinaryConsts::RefCastStatic || code == BinaryConsts::RefCast ||
       code == BinaryConsts::RefCastNull || code == BinaryConsts::RefCastNop) {
-    bool legacy =
-      code == BinaryConsts::RefCastStatic || code == BinaryConsts::RefCastNop;
+    bool legacy = code == BinaryConsts::RefCastStatic;
     auto heapType = legacy ? getIndexedHeapType() : getHeapType();
     auto* ref = popNonVoidExpression();
     Nullability nullability;

src/wasm/wasm-stack.cpp

@@ -2036,7 +2036,7 @@ void BinaryInstWriter::visitRefCast(RefCast* curr) {
   o << int8_t(BinaryConsts::GCPrefix);
   if (curr->safety == RefCast::Unsafe) {
     o << U32LEB(BinaryConsts::RefCastNop);
-    parent.writeIndexedHeapType(curr->type.getHeapType());
+    parent.writeHeapType(curr->type.getHeapType());
   } else {
     // TODO: These instructions are deprecated. Remove them.
     if (auto type = curr->type.getHeapType();

test/lit/ref-cast-nop.wast

@@ -15,4 +15,15 @@
    (local.get $x)
   )
  )
+
+ ;; CHECK:      (func $ref.cast_nop.null (type $ref|any|_=>_ref|none|) (param $x (ref any)) (result (ref none))
+ ;; CHECK-NEXT:  (ref.cast_nop none
+ ;; CHECK-NEXT:   (local.get $x)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ (func $ref.cast_nop.null (param $x (ref any)) (result (ref none))
+  (ref.cast_nop none
+   (local.get $x)
+  )
+ )
 )