Function rustc_middle::traits::util::supertraits_for_pretty_printing

pub fn supertraits_for_pretty_printing<'tcx>(
    tcx: TyCtxt<'tcx>,
    trait_ref: PolyTraitRef<'tcx>
) -> impl Iterator<Item = PolyTraitRef<'tcx>>

Given a PolyTraitRef, get the PolyTraitRefs of the trait’s (transitive) supertraits. This only exists in rustc_middle because the more powerful elaborator depends on rustc_infer for elaborating outlives bounds – this should only be used for pretty printing.