A DESCRIPTION OF THE REQUEST :
"Unsafe" casts produce a warning.
Generifying the class eliminates the warning, but can leave an extraneous cast that should be removed to improve readability. A warning would make it possible to determine which casts can safely be removed.

JUSTIFICATION :
Would help when converting legacy code to generics.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Rather than a lint option, this one should be a standard warning when you're using a parameterized type and the cast simply isn't needed.
ACTUAL -
No warning is delivered for an extraneous cast.

---------- BEGIN SOURCE ----------
public class CastWarning {
  public void test() {
    List<Integer> numbers = new LinkedList<Integer>();
    numbers.add(1);
    Integer i = (Integer) numbers.get(0); // Should get a warning
  }
}
---------- END SOURCE ----------