syntax_data: {"ast_node_type":"other","tokens":[{"end":37,"kind":"keyword","start":0,"text":"impl<'tcx>"}]}
source_snippet: impl<'tcx> OpaqueTypeExpander<'tcx> {
context_after:     fn expand_opaque_ty(&mut self, def_id: DefId, args: GenericArgsRef<'tcx>) -> Option<Ty<'tcx>> {