public @NotNull Collection<PsiImplicitClass> getElements(@NotNull String key,
                                                           @NotNull Project project,
                                                           @Nullable GlobalSearchScope scope) {
    return StubIndex.getElements(getKey(), key, project, scope, PsiImplicitClass.class);
  }
public @NotNull Collection<PsiImplicitClass> getElements(@NotNull String key,
                                                           @NotNull Project project,
                                                           @Nullable GlobalSearchScope scope)