syntax_data: {"ast_node_type":"function","tokens":[{"end":72,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:     let poll_fn = tcx.require_lang_item(LangItem::FuturePoll, DUMMY_SP);
context_before: ) -> BasicBlock {
context_after:     let poll_fn = Ty::new_fn_def(tcx, poll_fn, [fut_ty]);