**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.

componentName
          );
          manualPropTypeCallCache[cacheKey] = true;
        }
      }
    }
    if (props[propName] == null) {
      var locationName = ReactPropTypeLocationNames[location];
      if (isRequired) {
        return new Error(
          `Required ${locationName} \`${propFullName}\` was not specified in ` +
          `\`${componentName}\`.`
        );
      }
      return null;
    } else {
      return validate(
        props,
        propName,
        componentName,
        location,
        propFullName,
      );
    }
  }
  var chainedCheckType = checkType.bind(null, false);
  chainedCheckType.isRequired = checkType.bind(null, true);
  return chainedCheckType;
}
function createPrimitiveTypeChecker(expectedType) {