syntax_data: {"ast_node_type":"variable","tokens":[{"end":88,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let state_args = tcx.mk_args(&[old_yield_ty.into(), old_ret_ty.into()]);
context_before:                 let state_adt_ref = tcx.adt_def(state_did);
context_after:                 Ty::new_adt(tcx, state_adt_ref, state_args)