assertThrows(
        NullPointerException.class, () -> fluent(1, 2, 3).uniqueIndex(Functions.constant(null)));
  }

  public void testUniqueIndex_nullValue() {
    assertThrows(
        NullPointerException.class,
        () -> {
          ImmutableMap<Object, Integer> unused =
              fluent(1, null, 2)
                  .uniqueIndex(
                      new Function<Integer, Object>() {

	// In some db (e.g. MySQL), Unique and UniqueIndex are indistinguishable.
	// When a column has a (not Mul) UniqueIndex, Migrator always reports its gorm.ColumnType is Unique.
	// It causes field unnecessarily migration.
	// Therefore, we need to record the UniqueIndex on this column (exclude Mul UniqueIndex) for MigrateColumnUnique.
	UniqueIndex string
}

func (field *Field) BindName() string {

			PkgPath: ownField.StructField.PkgPath,
			Type:    ownField.StructField.Type,
			Tag: removeSettingFromTag(appendSettingFromTag(ownField.StructField.Tag, "primaryKey"),
				"column", "autoincrement", "index", "unique", "uniqueindex"),
		})
	}

	for idx, relField := range refForeignFields {
		joinFieldName := cases.Title(language.Und, cases.NoLower).String(relation.FieldSchema.Name) + relField.Name

	unique, ok := columnType.Unique()
	if !ok || field.PrimaryKey {
		return nil // skip primary key
	}
	// By default, ColumnType's Unique is not affected by UniqueIndex, so we don't care about UniqueIndex.
	return m.RunWithValue(value, func(stmt *gorm.Statement) error {
		// We're currently only receiving boolean values on `Unique` tag,
		// so the UniqueConstraint name is fixed

   * @since 10.0
   */
  @CanIgnoreReturnValue
  public static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction) {
    return uniqueIndex(values, keyFunction, ImmutableMap.builder());
  }

  private static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction, ImmutableMap.Builder<K, V> builder) {

   * @since 10.0
   */
  @CanIgnoreReturnValue
  public static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction) {
    return uniqueIndex(values, keyFunction, ImmutableMap.builder());
  }

  private static <K, V> ImmutableMap<K, V> uniqueIndex(
      Iterator<V> values, Function<? super V, K> keyFunction, ImmutableMap.Builder<K, V> builder) {

   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final <K> ImmutableMap<K, @NonNull E> uniqueIndex(Function<? super E, K> keyFunction) {
    return Maps.uniqueIndex((Iterable<@NonNull E>) getDelegate(), keyFunction);
  }

  /**
   * Returns an array containing all of the elements from this fluent iterable in iteration order.
   *

   * @since 14.0
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final <K> ImmutableMap<K, @NonNull E> uniqueIndex(Function<? super E, K> keyFunction) {
    return Maps.uniqueIndex((Iterable<@NonNull E>) getDelegate(), keyFunction);
  }

  /**
   * Returns an array containing all of the elements from this fluent iterable in iteration order.
   *

		}
		if field.UniqueIndex != uniqueIndex {
			t.Fatalf("%v: %q column %q uniqueIndex should be %v but got %v", utils.FileWithLineNum(), stmt.Schema, fieldName, uniqueIndex, field.UniqueIndex)
		}
	}

	type ( // not unique
		UniqueStruct1 struct {
			Name string `gorm:"size:10"`
		}

    ImmutableMap<Integer, String> outputMap =
        Maps.uniqueIndex(INT_TO_STRING_MAP.values(), Functions.forMap(INT_TO_STRING_MAP.inverse()));
    assertEquals(INT_TO_STRING_MAP, outputMap);
  }

  public void testUniqueIndexIterable() {
    ImmutableMap<Integer, String> outputMap =
        Maps.uniqueIndex(
            new Iterable<String>() {
              @Override