When creating an Element with a ref from inside of a constructor an error is thrown in production mode, but not in dev mode.

Here is a minimal sample:
https://jsfiddle.net/84v837e9/35/

An error, "Only a ReactOwner can have refs", should happen in dev and production modes.

This is happening in React 15.4
saveA = () => {
        refCalled++;
      };
      componentDidMount() {
        this.setState({});
      }
      render() {
        return <Inner saveA={this.saveA} />;
      }
    }
    ReactTestUtils.renderIntoDocument(<Outer />);
    expect(refCalled).toBe(1);
  }
  it('ref called correctly for stateless component when __DEV__ = false', () => {
    var originalDev = __DEV__;
    __DEV__ = false;
    testRefCall();
    __DEV__ = originalDev;
  });
  it('ref called correctly for stateless component when __DEV__ = true', () => {
    var originalDev = __DEV__;
    __DEV__ = true;
    testRefCall();
    __DEV__ = originalDev;
  });
  it('coerces numbers to strings', () => {
    class A extends React.Component {