syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":")"}]}
source_snippet:     ) -> Result<Option<FutureCompatOverlapError<'tcx>>, OverlapError<'tcx>> {
context_before:         overlap_mode: OverlapMode,
context_after:         assert!(impl_def_id.is_local());