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.
static contextType = Context;
      constructor(props, context) {
        super(props, context);
        constructorContext = context;
      }
      UNSAFE_componentWillReceiveProps(nextProps, nextContext) {
        componentWillReceivePropsContext = this.context;
        componentWillReceivePropsNextContext = nextContext;
        return true;
      }
      shouldComponentUpdate(nextProps, nextState, nextContext) {
        shouldComponentUpdateWasCalled = true;
        return true;
      }
      UNSAFE_componentWillUpdate(nextProps, nextState, nextContext) {
        componentWillUpdateContext = this.context;
        componentWillUpdateNextContext = nextContext;
      }
      render() {
        renderContext = this.context;
        return <div />;
      }
      componentDidMount() {
        componentDidMountContext = this.context;
      }
      componentDidUpdate() {
        componentDidUpdateContext = this.context;
      }
    }
    const firstContext = {foo: 123};