4 files changed, 6 insertions, 22 deletions
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index 386f89060..c6fb361bd 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -6920,14 +6920,6 @@ bool WasmBinaryBuilder::maybeVisitRefCast(Expression*& out, uint32_t code) {
     } else {
       nullability = code == BinaryConsts::RefCast ? NonNullable : Nullable;
     }
-    // Only accept instructions emulating the legacy behavior for now.
-    if (ref->type.isRef()) {
-      if (nullability == NonNullable && ref->type.isNullable()) {
-        throwError("ref.cast on nullable input not yet supported");
-      } else if (nullability == Nullable && ref->type.isNonNullable()) {
-        throwError("ref.cast null on non-nullable input not yet supported");
-      }
-    }
     auto safety =
       code == BinaryConsts::RefCastNop ? RefCast::Unsafe : RefCast::Safe;
     auto type = Type(heapType, nullability);
diff --git a/src/wasm/wasm-s-parser.cpp b/src/wasm/wasm-s-parser.cpp
index 4fdc29a66..2f791609a 100644
--- a/src/wasm/wasm-s-parser.cpp
+++ b/src/wasm/wasm-s-parser.cpp
@@ -2805,15 +2805,6 @@ Expression* SExpressionWasmBuilder::makeRefCast(Element& s) {
   if (legacy) {
     // Legacy polymorphic behavior.
     nullability = ref->type.getNullability();
-  } else if (ref->type.isRef()) {
-    // Only accept instructions emulating the legacy behavior for now.
-    if (nullability == NonNullable && ref->type.isNullable()) {
-      throw ParseException(
-        "ref.cast on nullable input not yet supported", s.line, s.col);
-    } else if (nullability == Nullable && ref->type.isNonNullable()) {
-      throw ParseException(
-        "ref.cast null on non-nullable input not yet supported", s.line, s.col);
-    }
   }
   auto type = Type(heapType, nullability);
   return Builder(wasm).makeRefCast(ref, type, RefCast::Safe);
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 68fb58ec4..bec9b0ad0 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -2535,11 +2535,11 @@ void FunctionValidator::visitRefCast(RefCast* curr) {
     curr,
     "ref.cast target type and ref type must have a common supertype");
 
-  // TODO: Remove this restriction
-  shouldBeEqual(curr->type.getNullability(),
-                curr->ref->type.getNullability(),
-                curr,
-                "ref.cast to a different nullability not yet implemented");
+  // We should never have a nullable cast of a non-nullable reference, since
+  // that unnecessarily loses type information.
+  shouldBeTrue(curr->ref->type.isNullable() || curr->type.isNonNullable(),
+               curr,
+               "ref.cast null of non-nullable references are not allowed");
 }
 
 void FunctionValidator::visitBrOn(BrOn* curr) {
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index cf71689b1..682936461 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -945,6 +945,7 @@ void RefTest::finalize() {
 void RefCast::finalize() {
   if (ref->type == Type::unreachable) {
     type = Type::unreachable;
+    return;
   }
   // Do not unnecessarily lose non-nullability information.
   if (ref->type.isNonNullable() && type.isNullable()) {