Function rustc_ty::instance::resolve_instance_of_const_arg

fn resolve_instance_of_const_arg<'tcx>(
    tcx: TyCtxt<'tcx>, 
    key: ParamEnvAnd<'tcx, (LocalDefId, DefId, SubstsRef<'tcx>)>
) -> Result<Option<Instance<'tcx>>, ErrorReported>