Function typeck_with_fallback

pub(crate) fn typeck_with_fallback<'tcx>(
    tcx: TyCtxt<'tcx>,
    def_id: LocalDefId,
    fallback: impl Fn() -> Ty<'tcx> + 'tcx,
    inspector: Option<ObligationInspector<'tcx>>,
) -> &'tcx TypeckResults<'tcx>