{"ast_node_type":"function","tokens":[{"end":57,"kind":"keyword","start":0,"text":"fn"}]}
        fn visit_expr(&mut self, ex: &'_ hir::Expr<'_>) {
    impl Visitor<'_> for UnsafeInferVarsVisitor<'_, '_> {
            let typeck_results = self.fcx.typeck_results.borrow();