pub(crate) fn upcast_choices<'db>(
interner: DbInterner<'db>,
source_trait_ref: PolyTraitRef<'db>,
target_trait_def_id: TraitId,
) -> Vec<PolyTraitRef<'db>> ⓘExpand description
Casts a trait reference into a reference to one of its super
traits; returns None if target_trait_def_id is not a
supertrait.