3 files changed, 20 insertions, 21 deletions
diff --git a/scripts/fuzz_opt.py b/scripts/fuzz_opt.py
index a591f9414..e7826c0f3 100755
--- a/scripts/fuzz_opt.py
+++ b/scripts/fuzz_opt.py
@@ -361,7 +361,7 @@ INITIAL_CONTENTS_IGNORE = [
     'shared-absheaptype.wast',
     'type-ssa-shared.wast',
     'shared-ref_eq.wast',
-    'shared-null-no-gc.wast',
+    'shared-types-no-gc.wast',
 ]
 
 
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index d35edadc8..20815b701 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -1520,23 +1520,15 @@ void WasmBinaryWriter::writeType(Type type) {
     // internally use more refined versions of those types, but we cannot emit
     // those more refined types.
     if (!wasm->features.hasGC()) {
-      if (Type::isSubType(type, Type(HeapType::func, Nullable))) {
-        o << S32LEB(BinaryConsts::EncodedType::funcref);
-        return;
-      }
-      if (Type::isSubType(type, Type(HeapType::ext, Nullable))) {
-        o << S32LEB(BinaryConsts::EncodedType::externref);
-        return;
-      }
-      if (Type::isSubType(type, Type(HeapType::exn, Nullable))) {
-        o << S32LEB(BinaryConsts::EncodedType::exnref);
-        return;
-      }
-      if (Type::isSubType(type, Type(HeapType::string, Nullable))) {
-        o << S32LEB(BinaryConsts::EncodedType::stringref);
-        return;
+      auto ht = type.getHeapType();
+      if (ht.isBasic() && ht.getBasic(Unshared) == HeapType::string) {
+        // Do not overgeneralize stringref to anyref. We have tests that when a
+        // stringref is expected, we actually get a stringref. If we see a
+        // string, the stringref feature must be enabled.
+        type = Type(HeapTypes::string.getBasic(ht.getShared()), Nullable);
+      } else {
+        type = Type(type.getHeapType().getTop(), Nullable);
       }
-      WASM_UNREACHABLE("bad type without GC");
     }
     auto heapType = type.getHeapType();
     if (type.isNullable() && heapType.isBasic() && !heapType.isShared()) {
diff --git a/test/lit/basic/shared-null-no-gc.wast b/test/lit/basic/shared-types-no-gc.wast
index b920f80f8..94c664f58 100644
--- a/test/lit/basic/shared-null-no-gc.wast
+++ b/test/lit/basic/shared-types-no-gc.wast
@@ -1,19 +1,26 @@
 ;; NOTE: Assertions have been generated by update_lit_checks.py and should not be edited.
 
-;; Test that we can write a binary without crashing when using a shared bottom
-;; type without GC enabled.
+;; Test that we can write a binary without crashing when using shared reference
+;; types without GC enabled.
 
 ;; RUN: wasm-opt %s --enable-reference-types --enable-shared-everything --roundtrip -S -o - | filecheck %s
 
 (module
- ;; CHECK:      (func $test
+ ;; CHECK:      (func $null
  ;; CHECK-NEXT:  (drop
  ;; CHECK-NEXT:   (ref.null (shared nofunc))
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
- (func $test
+ (func $null
   (drop
    (ref.null (shared func))
   )
  )
+
+ ;; CHECK:      (func $signature (result (ref null (shared func)))
+ ;; CHECK-NEXT:  (unreachable)
+ ;; CHECK-NEXT: )
+ (func $signature (result (ref null (shared func)))
+  (unreachable)
+ )
 )