1 files changed, 12 insertions, 1 deletions
diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index a94bda066..f8d8890ec 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -936,13 +936,24 @@ void BrOn::finalize() {
       (rtt && rtt->type == Type::unreachable)) {
     type = Type::unreachable;
   } else {
-    type = ref->type;
+    if (op == BrOnNull) {
+      // If BrOnNull does not branch, it flows out the existing value as
+      // non-null.
+      // FIXME: When we support non-nullable types, this should be non-nullable.
+      type = Type(ref->type.getHeapType(), Nullable);
+    } else {
+      type = ref->type;
+    }
   }
 }
 
 Type BrOn::getCastType() {
   switch (op) {
+    case BrOnNull:
+      // BrOnNull does not send a value on the branch.
+      return Type::none;
     case BrOnCast:
+      // FIXME: When we support non-nullable types, this should be non-nullable.
       return Type(rtt->type.getHeapType(), Nullable);
     case BrOnFunc:
       return Type::funcref;