This usually means that the user mixed up our lowercase/uppercase naming convention; see https://github.com/facebook/react/pull/3429#issuecomment-85166440.

We could add a message like

> Warning: The tag <commentBox> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.

We'd check this only once per tag and only in development mode.

render() {
          return <table>{this.props.children}</table>;
        }
      }
      class FancyTable extends React.Component {
        render() {
          return <Table>{this.props.children}</Table>;
        }
      }
      function Viz1() {
        return <table><FancyRow /></table>;
      }
      function App1() {
        return <Viz1 />;
      }
      ReactTestUtils.renderIntoDocument(<App1 />);
      expectDev(console.error.calls.count()).toBe(1);
      expectDev(
        normalizeCodeLocInfo(console.error.calls.argsFor(0)[0]),
      ).toContain(
        ReactDOMFeatureFlags.useFiber
          ? '\n    in tr (at **)' +
              '\n    in Row (at **)' +
              '\n    in FancyRow (at **)' +
              '\n    in table (at **)' +
              '\n    in Viz1 (at **)'
          : 'See Viz1 > table > FancyRow > Row > tr.',
      );
      function Viz2() {