syntax_data: {"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().skip_binder();
context_before:         // FIXME: use `EarlyBinder` in `self.children`
context_after:         let trait_def_id = trait_ref.def_id;