syntax_data: {"ast_node_type":"variable","tokens":[{"end":89,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let ty::FnPtr(sig_tys, hdr) = self.signature_parts_ty().kind() else { panic!() };
context_before:     pub fn coroutine_closure_sig(self) -> ty::Binder<I, CoroutineClosureSignature<I>> {
context_after:         sig_tys.map_bound(|sig_tys| {