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.
constructor(props, context) {
        super(props, context);
        this.state = {tag: context.tag, className: this.context.className};
      }
      render() {
        var Tag = this.state.tag;
        return <Tag className={this.state.className} />;
      }
    }
    Foo.contextTypes = {
      tag: PropTypes.string,
      className: PropTypes.string,
    };
    class Outer extends React.Component {
      getChildContext() {
        return {tag: 'span', className: 'foo'};
      }
      render() {
        return <Foo />;
      }
    }
    Outer.childContextTypes = {
      tag: PropTypes.string,
      className: PropTypes.string,
    };
    test(<Outer />, 'SPAN', 'foo');
  });
  it('renders only once when setting state in componentWillMount', () => {
    var renderCount = 0;
    class Foo extends React.Component {