{"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
        let bound_sig = self.normalize_associated_types_in(bound_sig);
            self.sig_of_closure(body, ret_type, arg_types, closure_kind, expected_sig);
        let sig_ty = TyKind::Function(bound_sig.clone()).intern(Interner);