message: More deterministic
  Summary: By sorting the `to_optimize` list.
diff: @@ -534,6 +534,7 @@ size_t OptimizationImpl::optimize(
  Scope& scope, const SingleImplConfig& config) {
  TypeList to_optimize;
  single_impls->get_interfaces(to_optimize);
  + std::sort(to_optimize.begin(), to_optimize.end(), compare_dextypes);
  for (auto intf : to_optimize) {
  auto& intf_data = single_impls->get_single_impl_data(intf);
  if (intf_data.is_escaped()) continue;
  