{"ast_node_type":"function","tokens":[{"end":86,"kind":"keyword","start":0,"text":"fn"}]}
    fn mutate(&mut self, assignee_place: &PlaceWithHirId<'tcx>, diag_expr_id: HirId) {
    #[instrument(skip(self), level = "debug")]
        self.borrow(assignee_place, diag_expr_id, ty::BorrowKind::Mutable);