syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":")"}]}
source_snippet:     ) -> Normalized<'tcx, GenericArgsRef<'tcx>> {
context_before:         obligation: &PolyTraitObligation<'tcx>,
context_after:         let impl_trait_header = self.tcx().impl_trait_header(impl_def_id).unwrap();