{"ast_node_type":"function","tokens":[{"end":76,"kind":"keyword","start":0,"text":"fn"}]}
    fn expr_ty(&self, expr: &hir::Expr<'_>) -> Result<Ty<'tcx>, Cx::Error> {
        self.expect_and_resolve_type(expr.hir_id, self.cx.typeck_results().expr_ty_opt(expr))