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() {
          super();
          this.state = state;
        }
        render() {
          return <span />;
        }
      }
      if (__DEV__) {
        expect(() => test(<Foo />, 'SPAN', '')).toThrowError(
          'Foo.state: must be set to an object or null',
        );
      } else {
        
        
        
        
        expect(() => test(<Foo />, 'SPAN', '')).not.toThrowError();
      }
    });
  });
  it('should render with null in the initial state property', () => {
    class Foo extends React.Component {