Do not test for op-assignment when not ending with '='.
@@ -295,7 +295,7 @@ impl Engine {
None => (),
}
- if is_ref {
+ if is_ref && fn_name.ends_with('=') {
let (first, second) = args.split_first_mut().unwrap();
match run_builtin_op_assignment(fn_name, first, second[0])? {
