After a discussion with @spicyj we decided to keep the warning even though the functions will throw in production. The warning is the only way to learn about that.

We should also document how to pass the secret through in case you know what you're doing.

typeCheckPass(
        PropTypes.shape(PropTypes.shape({key: PropTypes.number})), undefined
      );
    });
    it('should warn for missing required values', () => {
      typeCheckFailRequiredValues(
        PropTypes.shape({key: PropTypes.number}).isRequired
      );
    });
  });
  describe('Symbol Type', () => {
    it('should warn for non-symbol', () => {
      typeCheckFail(
        PropTypes.symbol,
        'hello',
        'Invalid prop `testProp` of type `string` supplied to ' +
        '`testComponent`, expected `symbol`.'
      );
      typeCheckFail(
        PropTypes.symbol,
        function() { },
        'Invalid prop `testProp` of type `function` supplied to ' +
        '`testComponent`, expected `symbol`.'
      );
      typeCheckFail(
        PropTypes.symbol,
        {
          '@@toStringTag': 'Katana',
        },
        'Invalid prop `testProp` of type `object` supplied to ' +