[Wasm GC] Fix non-nullable tuples (#4555)

Apply the same logic to tuple fields as we do for all other fields,
when checking whether a non-nullable value is valid.

Fixes #4554

2 files changed, 16 insertions, 4 deletions

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,