{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"dyn_ty:"}]}
        dyn_ty: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
        ty: Ty<'tcx>,
    ) -> InterpResult<'tcx, Pointer<Option<M::Provenance>>> {