Node name collision for unique argument

module foo {
  namespace "urn:foo";
  prefix "foo";

  grouping bar-group {
    list bar {
      key bar;
      unique baz;

      leaf bar {
        type string;
      }

      leaf baz {
        type string;
      }
    }
  }

  grouping foo-group {
    container foo {
      uses bar-group;
    }
  }

  uses foo-group;
}

Caused by: org.opendaylight.yangtools.yang.parser.spi.source.SourceException: Error in module 'foo': cannot add '(urn:foo)baz'. Node name collision: '(urn:foo)baz' already declared at foo.yang:14:7 [at foo.yang:14:7]