syntax_data: {"ast_node_type":"variable","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let option_did = tcx.require_lang_item(LangItem::Option, DUMMY_SP);
context_before:                     // The signature should be `Iterator::next(_) -> Option<Yield>`
context_after:                     let option_adt_ref = tcx.adt_def(option_did);