syntax_data: {"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"coroutine_def_id,"}]}
source_snippet:                                         coroutine_def_id,
context_before:                                         self.tcx(),
context_after:                                         self.tcx().mk_args(args.as_coroutine().parent_args()),