syntax_data: {"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"tcx.require_lang_item(LangItem::AsyncGenPending,"}]}
source_snippet:                             tcx.require_lang_item(LangItem::AsyncGenPending, source_info.span),
context_before:                         UnevaluatedConst::new(
context_after:                             tcx.mk_args(&[yield_ty.into()]),