Just about every time I set up a new `Context.Provider`, I end up accidentally specifying a `values` prop rather than `value`.  While it's a minor error, generally I build the container in which the provider resides and commit it to the code base before I ever use it.  It's only later when I go to use it that I realize I did it again.  Since the `Context.Provider` seems pretty much useless without a `value` prop specified, I'd love it if there was a prop error if it is missing... especially if another prop is defined on the `Context.Provider` instead.
render() {
        log.push('Angry render');
        throw new Error('Please, do not render me.');
      }
      componentDidMount() {
        log.push('Angry componentDidMount');
      }
      componentWillUnmount() {
        log.push('Angry componentWillUnmount');
      }
    }
    class Boundary extends React.Component {
      constructor(props) {
        super(props);
        this.state = {error: false};
      }
      render() {
        log.push('Boundary render');
        if (!this.state.error) {
          return (
            <div>
              <button onClick={this.onClick}>ClickMe</button>
              <Angry />
            </div>
          );
        } else {
          return <div>Happy Birthday!</div>;
        }
      }
      componentDidMount() {