Function rustc_trait_selection::traits::util::closure_trait_ref_and_return_type

pub fn closure_trait_ref_and_return_type<'tcx>(
    tcx: TyCtxt<'tcx>, 
    fn_trait_def_id: DefId, 
    self_ty: Ty<'tcx>, 
    sig: PolyFnSig<'tcx>, 
    tuple_arguments: TupleArgumentsFlag
) -> Binder<(TraitRef<'tcx>, Ty<'tcx>)>