See this example: https://github.com/facebook/react/issues/11508#issuecomment-345464797.

I think it probably reflects a misunderstanding of how props and state work, and we should detect and warn if we see this.
'instance: you may have forgotten to define `render`.',
          name,
        );
      }
    }
    const noGetInitialStateOnES6 =
      !instance.getInitialState ||
      instance.getInitialState.isReactClassApproved ||
      instance.state;
    warningWithoutStack(
      noGetInitialStateOnES6,
      'getInitialState was defined on %s, a plain JavaScript class. ' +
        'This is only supported for classes created using React.createClass. ' +
        'Did you mean to define a state property instead?',
      name,
    );
    const noGetDefaultPropsOnES6 =
      !instance.getDefaultProps ||
      instance.getDefaultProps.isReactClassApproved;
    warningWithoutStack(
      noGetDefaultPropsOnES6,
      'getDefaultProps was defined on %s, a plain JavaScript class. ' +
        'This is only supported for classes created using React.createClass. ' +
        'Use a static property to define defaultProps instead.',
      name,
    );
    const noInstancePropTypes = !instance.propTypes;
    warningWithoutStack(
      noInstancePropTypes,
      'propTypes was defined as an instance property on %s. Use a static ' +