Function rustc_trait_selection::traits::util::get_vtable_index_of_object_method

pub fn get_vtable_index_of_object_method<N, 'tcx>(
    tcx: TyCtxt<'tcx>, 
    object: &ImplSourceObjectData<'tcx, N>, 
    method_def_id: DefId
) -> usize

Given an upcast trait object described by object, returns the index of the method method_def_id (which should be part of object.upcast_trait_ref) within the vtable for object.