5 files changed, 43 insertions, 7 deletions

diff --git a/src/tools/wasm-shell.cpp b/src/tools/wasm-shell.cpp
index 0de93c69e..2d0fbf14c 100644
--- a/src/tools/wasm-shell.cpp
+++ b/src/tools/wasm-shell.cpp
@@ -134,7 +134,7 @@ protected:
     lastModule = module->name;
     builders[moduleName] = builder;
     modules[moduleName].swap(module);
-    modules[moduleName]->features = FeatureSet::All;
+    modules[moduleName]->features.setAll();
     bool valid = WasmValidator().validate(*modules[moduleName]);
     if (!valid) {
       std::cout << *modules[moduleName] << '\n';
@@ -237,7 +237,7 @@ protected:
 
   void parseModuleAssertion(Element& s) {
     Module wasm;
-    wasm.features = FeatureSet::All;
+    wasm.features.setAll();
     std::unique_ptr<SExpressionWasmBuilder> builder;
     auto id = s[0]->str();
 
@@ -358,7 +358,7 @@ protected:
       "memory", spectest->memory.name, ExternalKind::Memory));
 
     modules["spectest"].swap(spectest);
-    modules["spectest"]->features = FeatureSet::All;
+    modules["spectest"]->features.setAll();
     instantiate(modules["spectest"].get());
     linkedInstances["spectest"] = instances["spectest"];
     // print_* functions are handled separately, no need to define here.
diff --git a/src/wasm-type.h b/src/wasm-type.h
index 05deeef15..4d908fe05 100644
--- a/src/wasm-type.h
+++ b/src/wasm-type.h
@@ -186,6 +186,13 @@ public:
   bool isArray() const;
   bool isDefaultable() const;
 
+  // Check if a type is either defaultable or non-nullable. This is useful in
+  // the case where we allow non-nullable types, but we disallow other things
+  // that are non-defaultable. For example, when GC-non-nullable references are
+  // allowed we can have  a non-nullable reference, but we cannot have any other
+  // nondefaultable type.
+  bool isDefaultableOrNonNullable() const;
+
   Nullability getNullability() const;
 
 private:
diff --git a/src/wasm/wasm-type.cpp b/src/wasm/wasm-type.cpp
index ea4e43efe..ce823aae0 100644
--- a/src/wasm/wasm-type.cpp
+++ b/src/wasm/wasm-type.cpp
@@ -1021,6 +1021,18 @@ bool Type::isDefaultable() const {
   return isConcrete() && !isNonNullable() && !isRtt();
 }
 
+bool Type::isDefaultableOrNonNullable() const {
+  if (isTuple()) {
+    for (auto t : *this) {
+      if (!t.isDefaultableOrNonNullable()) {
+        return false;
+      }
+    }
+    return true;
+  }
+  return isConcrete() && !isRtt();
+}
+
 Nullability Type::getNullability() const {
   return isNullable() ? Nullable : NonNullable;
 }
diff --git a/src/wasm/wasm-validator.cpp b/src/wasm/wasm-validator.cpp
index 86fc4811b..8d35543fc 100644
--- a/src/wasm/wasm-validator.cpp
+++ b/src/wasm/wasm-validator.cpp
@@ -2728,11 +2728,11 @@ void FunctionValidator::visitFunction(Function* curr) {
     shouldBeTrue(result.isConcrete(), curr, "results must be concretely typed");
   }
   for (const auto& var : curr->vars) {
-    if (var.isRef() && getModule()->features.hasGCNNLocals()) {
-      continue;
-    }
     features |= var.getFeatures();
-    shouldBeTrue(var.isDefaultable(), var, "vars must be defaultable");
+    bool valid = getModule()->features.hasGCNNLocals()
+                   ? var.isDefaultableOrNonNullable()
+                   : var.isDefaultable();
+    shouldBeTrue(valid, var, "vars must be defaultable");
   }
   shouldBeTrue(features <= getModule()->features,
                curr->name,
diff --git a/test/lit/validation/nn-tuples.wast b/test/lit/validation/nn-tuples.wast
new file mode 100644
index 000000000..452a6c77e
--- /dev/null
+++ b/test/lit/validation/nn-tuples.wast
@@ -0,0 +1,17 @@
+;; Test for non-nullable types in tuples
+
+;; RUN: not wasm-opt -all %s 2>&1 | filecheck %s --check-prefix NO-NN-LOCALS
+;; RUN:     wasm-opt -all %s --enable-gc-nn-locals -o - -S | filecheck %s --check-prefix NN-LOCALS
+
+;; NO-NN-LOCALS: vars must be defaultable
+
+;; NN-LOCALS: (module
+;; NN-LOCALS:  (local $tuple ((ref any) (ref any)))
+;; NN-LOCALS:  (nop)
+;; NN-LOCALS: )
+
+(module
+  (func $foo
+    (local $tuple ((ref any) (ref any)))
+  )
+)