syntax_data: {"ast_node_type":"variable","tokens":[{"end":92,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let option_def_id = self.tcx.require_lang_item(LangItem::Option, body.span);
context_before:             CoroutineKind::Desugared(CoroutineDesugaring::Gen, _) => {
context_after:                 make_aggregate_adt(