syntax_data: {"ast_node_type":"variable","tokens":[{"end":95,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let poll_def_id = self.tcx.require_lang_item(LangItem::Poll, source_info.span);
context_before:             CoroutineKind::Desugared(CoroutineDesugaring::Async, _) => {
context_after:                 let args = self.tcx.mk_args(&[self.old_ret_ty.into()]);