**Do you want to request a _feature_ or report a _bug_?**
Enhancement

**What is the current behavior?**
Element type checker is not as informative as the other ones.

**What is the expected behavior?**
It would be nice to provide the actual type of the prop passed similarly to other type checkers. I.e., instead of 

> Invalid prop `Prop` supplied to `Component`, expected a single ReactElement.

say

> Invalid prop `Prop` of type `type` supplied to `Component`, expected a single ReactElement.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Seeing this on 15.2.1 but I think it's also applicable to previous versions.

I know the general intention is to move away from prop types, but if there isn't a specific reason for the current behavior I can look into making this more pretty.

]);
      typeCheckPass(checker, null);
      typeCheckPass(checker, 'foo');
      typeCheckPass(checker, 123);
      checker = PropTypes.oneOfType([
        PropTypes.shape({a: PropTypes.number.isRequired}),
        PropTypes.shape({b: PropTypes.number.isRequired}),
      ]);
      typeCheckPass(checker, {a: 1});
      typeCheckPass(checker, {b: 1});
    });
    it('should be implicitly optional and not warn without values', function() {
      typeCheckPass(
        PropTypes.oneOfType([PropTypes.string, PropTypes.number]), null
      );
      typeCheckPass(
        PropTypes.oneOfType([PropTypes.string, PropTypes.number]), undefined
      );
    });
    it('should warn for missing required values', function() {
      typeCheckFail(
        PropTypes.oneOfType([PropTypes.string, PropTypes.number]).isRequired,
        null,
        requiredMessage
      );
      typeCheckFail(
        PropTypes.oneOfType([PropTypes.string, PropTypes.number]).isRequired,
        undefined,
        requiredMessage
      );