syntax_data: {"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let impl_trait_ref = tcx.impl_trait_ref(impl_def_id);
context_before:         let self_ty = tcx.type_of(impl_def_id);
context_after:         let (self_ty, impl_trait_ref) = if tcx.generics_of(impl_def_id).count() <= args.len() {