{"ast_node_type":"function","tokens":[{"end":98,"kind":"keyword","start":0,"text":"fn"}]}
    fn compute_subtype_goal(&mut self, goal: Goal<I, ty::SubtypePredicate<I>>) -> QueryResult<I> {
    #[instrument(level = "trace", skip(self))]
        if goal.predicate.a.is_ty_var() && goal.predicate.b.is_ty_var() {