syntax_data: {"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let tys = match tcx.impl_trait_ref(def_id) {
context_before:             // inherent impls.
context_after:                 Some(trait_ref) => trait_ref.skip_binder().args.types().collect(),