syntax_data: {"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"(ty::Adt(a_def,"}]}
source_snippet:         (ty::Adt(a_def, a_args), ty::Adt(b_def, b_args)) if a_def == b_def => {
context_after:             Ok(if a_args.is_empty() {