syntax_data: {"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"self.tcx.require_lang_item(LangItem::CoroutineState,"}]}
source_snippet:                     self.tcx.require_lang_item(LangItem::CoroutineState, source_info.span);
context_before:                 let coroutine_state_def_id =
context_after:                 let args = self.tcx.mk_args(&[self.old_yield_ty.into(), self.old_ret_ty.into()]);