Fix error message handling

src/check_decl.cpp

@@ -1619,7 +1619,7 @@ gb_internal bool check_proc_body(CheckerContext *ctx_, Token token, DeclInfo *de
 				if (e->kind != Entity_Variable) {
 					continue;
 				}
-				if (is_type_polymorphic(e->type)) {
+				if (is_type_polymorphic(e->type) && is_type_polymorphic_record_unspecialized(e->type)) {
 					gbString s = type_to_string(e->type);
 					char const *msg = "Unspecialized polymorphic types are not allowed in procedure parameters, got %s";
 					if (e->Variable.type_expr) {

src/types.cpp

@@ -2100,8 +2100,8 @@ gb_internal bool is_type_polymorphic_record_unspecialized(Type *t) {
 	t = base_type(t);
 	if (t->kind == Type_Struct) {
 		return t->Struct.is_polymorphic && !t->Struct.is_poly_specialized;
-	} else if (t->kind == Type_Struct) {
-		return t->Struct.is_polymorphic && !t->Struct.is_poly_specialized;
+	} else if (t->kind == Type_Union) {
+		return t->Union.is_polymorphic && !t->Union.is_poly_specialized;
 	}
 	return false;
 }