{"ast_node_type":"other","tokens":[{"end":1,"kind":"keyword","start":0,"text":"{"}]}
{
    T: Copy + fmt::Display + TypeFoldable<TyCtxt<'tcx>> + 'tcx,
    fn fallback_error(&self, tcx: TyCtxt<'tcx>, span: Span) -> Diag<'tcx> {