{"ast_node_type":"other","tokens":[{"end":32,"kind":"keyword","start":0,"text":")"}]}
    ) -> ObligationCause<'tcx> {
        variant: impl FnOnce(DerivedHostCause<'tcx>) -> ObligationCauseCode<'tcx>,
        self.code = variant(DerivedHostCause { parent_host_pred, parent_code: self.code }).into();