pub fn elaborate_trait_refs<'tcx>(
    tcx: TyCtxt<'tcx>,
    trait_refs: impl Iterator<Item = PolyTraitRef<'tcx>>
) -> Elaborator<'tcx>Notable traits for Elaborator<'tcx>impl<'tcx> Iterator for Elaborator<'tcx> type Item = PredicateObligation<'tcx>;