fn insert_required_predicates_to_be_wf<'tcx>(
    tcx: TyCtxt<'tcx>,
    field_ty: Ty<'tcx>,
    field_span: Span,
    global_inferred_outlives: &FxHashMap<DefId, EarlyBinder<BTreeMap<OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>, Span>>>,
    required_predicates: &mut BTreeMap<OutlivesPredicate<GenericArg<'tcx>, Region<'tcx>>, Span>,
    explicit_map: &mut ExplicitPredicatesMap<'tcx>
)