Replace `RefIs` with `RefIsNull` (#5401)

* Replace `RefIs` with `RefIsNull`

The other `ref.is*` instructions are deprecated and expressible in terms of
`ref.test`. Update binary and text parsing to parse those instructions as
`RefTest` expressions. Also update the printing and emitting of `RefTest`
expressions to emit the legacy instructions for now to minimize test changes and
make this a mostly non-functional change. Since `ref.is_null` is the only
`RefIs` instruction left, remove the `RefIsOp` field and rename the expression
class to `RefIsNull`.

The few test changes are due to the fact that `ref.is*` instructions are now
subject to `ref.test` validation, and in particular it is no longer valid to
perform a `ref.is_func` on a value outside of the `func` type hierarchy.

1 files changed, 1 insertions, 2 deletions

diff --git a/src/tools/fuzzing/fuzzing.cpp b/src/tools/fuzzing/fuzzing.cpp
index cda14c989..18568271b 100644
--- a/src/tools/fuzzing/fuzzing.cpp
+++ b/src/tools/fuzzing/fuzzing.cpp
@@ -2954,11 +2954,10 @@ Expression* TranslateToFuzzReader::makeBulkMemory(Type type) {
   WASM_UNREACHABLE("invalid value");
 }
 
-// TODO: support other RefIs variants, and rename this
 Expression* TranslateToFuzzReader::makeRefIsNull(Type type) {
   assert(type == Type::i32);
   assert(wasm.features.hasReferenceTypes());
-  return builder.makeRefIs(RefIsNull, make(getReferenceType()));
+  return builder.makeRefIsNull(make(getReferenceType()));
 }
 
 Expression* TranslateToFuzzReader::makeRefEq(Type type) {