syntax_data: {"ast_node_type":"variable","tokens":[{"end":80,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let args = relation.relate_item_args(a_def_id, a_args, b_args)?;
context_before:             } else {
context_after:                 if args == a_args { a } else { Ty::new_fn_def(cx, a_def_id, args) }