Function rustc_trait_selection::traits::vtable::count_own_vtable_entries

pub(crate) fn count_own_vtable_entries<'tcx>(
    tcx: TyCtxt<'tcx>,
    trait_ref: PolyTraitRef<'tcx>
) -> usize

Given a trait trait_ref, returns the number of vtable entries that come from trait_ref, excluding its supertraits. Used in computing the vtable base for an upcast trait of a trait object.