syntax_data: {"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let ret_ty = Ty::new_adt(tcx, state_adt_ref, state_args);
context_before:                     let state_args = tcx.mk_args(&[sig.yield_ty.into(), sig.return_ty.into()]);