syntax_data: {"ast_node_type":"variable","tokens":[{"end":95,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let args = &tcx.impl_trait_ref(item).unwrap().instantiate_identity().args[1..];
context_before:                 let span = tcx.hir_node_by_def_id(item).expect_item().expect_impl().of_trait.unwrap().path.span;
context_after:                 try_visit!(visitor.visit(span, args));