{"ast_node_type":"variable","tokens":[{"end":86,"kind":"keyword","start":0,"text":"_"}]}
            _ if let Some(e) = self.tainted_by_errors() => Ty::new_error(self.tcx, e),
        let fallback = match ty.kind() {
            ty::Infer(ty::IntVar(_)) => self.tcx.types.i32,