Update reference types (#3084)

Align with the current state of the reference types proposal:
* Remove `nullref`
* Remove `externref` and `funcref` subtyping
* A `Literal` of a nullable reference type can now represent `null` (previously was type `nullref`)
* Update the tests and temporarily comment out those tests relying on subtyping

1 files changed, 4 insertions, 4 deletions

diff --git a/src/ir/properties.h b/src/ir/properties.h
index 0c6824e4a..ac61f787e 100644
--- a/src/ir/properties.h
+++ b/src/ir/properties.h
@@ -93,10 +93,10 @@ inline bool isConstantExpression(const Expression* curr) {
 inline Literal getSingleLiteral(const Expression* curr) {
   if (auto* c = curr->dynCast<Const>()) {
     return c->value;
-  } else if (curr->is<RefNull>()) {
-    return Literal(Type::nullref);
-  } else if (auto* c = curr->dynCast<RefFunc>()) {
-    return Literal(c->func);
+  } else if (auto* n = curr->dynCast<RefNull>()) {
+    return Literal(n->type);
+  } else if (auto* r = curr->dynCast<RefFunc>()) {
+    return Literal(r->func);
   } else {
     WASM_UNREACHABLE("non-constant expression");
   }