Follow up from https://github.com/facebook/react/pull/11616.

Here's one I found. These two invariants:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L330-L343

are in a function that's behind a DEV block:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L447-L449

I don't think this is intentional, but need to verify.

There may be more. I'll use this issue to track while https://github.com/facebook/react/pull/11616 preserves existing behavior.
expect(Foo.name).toBe('Foo');
  });
  it('throws if no render function is defined', () => {
    spyOnDev(console, 'error');
    class Foo extends React.Component {}
    expect(() => ReactDOM.render(<Foo />, container)).toThrow();
    if (__DEV__) {
      expect(console.error.calls.count()).toBe(1);
      expect(console.error.calls.argsFor(0)[0]).toBe(
        'Warning: Foo(...): No `render` method found on the returned component ' +
          'instance: you may have forgotten to define `render`.',
      );
    }
  });
  it('renders a simple stateless component with prop', () => {
    class Foo extends React.Component {
      render() {
        return <Inner name={this.props.bar} />;
      }
    }
    test(<Foo bar="foo" />, 'DIV', 'foo');
    test(<Foo bar="bar" />, 'DIV', 'bar');
  });
  it('renders based on state using initial values in this.props', () => {
    class Foo extends React.Component {
      constructor(props) {
        super(props);
        this.state = {bar: this.props.initialValue};
      }
      render() {