{"ast_node_type":"other","tokens":[{"end":97,"kind":"keyword","start":0,"text":"TyKind::RigidTy(RigidTy::FnDef(def,"}]}
            TyKind::RigidTy(RigidTy::FnDef(def, args)) => Some(with(|cx| cx.fn_sig(*def, args))),
        match self {
            TyKind::RigidTy(RigidTy::FnPtr(sig)) => Some(sig.clone()),