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**Do you want to request a *feature* or report a *bug*?**

Bug.

**What is the current behavior?**

Creating an `<input type='submit'` with `value={undefined}` results in a button with no text. https://codesandbox.io/s/nn7p94y3rl

The same behaviour can be seen with `type='reset'`

I have a PR open with a proposed fix. https://github.com/facebook/react/pull/12780

**What is the expected behavior?**

The input should use the browser's default value for the input (Submit for en, etc.).

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

React 16.3.2. Chrome 66.0.3359.139. macOS 10.13.4. Works in React 15 (unsure of earlier versions)

ReactDOM.render(
        <input
          type="radio"
          checked={true}
          defaultChecked={true}
          readOnly={true}
        />,
        container,
      ),
    ).toWarnDev(
      'A component contains an input of type radio with both checked and defaultChecked props. ' +
        'Input elements must be either controlled or uncontrolled ' +
        '(specify either the checked prop, or the defaultChecked prop, but not ' +
        'both). Decide between using a controlled or uncontrolled input ' +
        'element and remove one of these props. More info: ' +
        'https://fb.me/react-controlled-components',
    );
    ReactDOM.unmountComponentAtNode(container);
    ReactDOM.render(
      <input
        type="radio"
        checked={true}
        defaultChecked={true}
        readOnly={true}
      />,
      container,
    );
  });
  it('should warn if value and defaultValue props are specified', () => {
    expect(() =>