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() {
        const {special, children} = this.props;
        return <Foo className={special ? 'special' : 'normal'}>{children}</Foo>;
      }
    }
    
    class Bam extends React.Component {
      render() {
        return (
          <Bar special={true}>
            <Qoo />
          </Bar>
        );
      }
    }
    const renderer = ReactTestRenderer.create(<Bam />);
    const tree = renderer.toTree();