fix ChildTyper expected fields

src/ir/child-typer.h

@@ -997,7 +997,7 @@ template<typename Subtype> struct ChildTyper : OverriddenVisitor<Subtype> {
     const auto& fields = ht->getStruct().fields;
     assert(curr->index < fields.size());
     note(&curr->ref, Type(*ht, Nullable));
-    note(&curr->expected, fields[curr->index].type);
+    note(&curr->expected, Type(HeapType::eq, Nullable));
     note(&curr->replacement, fields[curr->index].type);
   }
 
@@ -1151,7 +1151,7 @@ template<typename Subtype> struct ChildTyper : OverriddenVisitor<Subtype> {
     auto type = ht->getArray().element.type;
     note(&curr->ref, Type(*ht, Nullable));
     note(&curr->index, Type::i32);
-    note(&curr->expected, type);
+    note(&curr->expected, Type(HeapType::eq, Nullable));
     note(&curr->replacement, type);
   }