Reference types changes to remove subtyping (#1407)

Main changes:
* Rename `anyref` -> `externref`
* Remove `nullref`
* Rename `hostref` -> `externref`
* `ref.null` and `ref.is_null` now have "ref kind" parameter
* Add ref kind keywords: `func`, `extern`, `exn`

1 files changed, 3 insertions, 10 deletions

diff --git a/src/interp/interp-inl.h b/src/interp/interp-inl.h
index 7650ff1b..0d306ebe 100644
--- a/src/interp/interp-inl.h
+++ b/src/interp/interp-inl.h
@@ -365,16 +365,9 @@ template <typename T> void RequireType(ValueType type) {
 }
 
 inline bool TypesMatch(ValueType expected, ValueType actual) {
-  if (expected == actual) {
-    return true;
-  }
-  if (!IsReference(expected)) {
-    return false;
-  }
-  if (expected == ValueType::Anyref || actual == ValueType::Nullref) {
-    return true;
-  }
-  return false;
+  // Currently there is no subtyping, so expected and actual must match
+  // exactly. In the future this may be expanded.
+  return expected == actual;
 }
 
 //// Value ////