unsigned short shift-assignment should warn about loss of precision

FULL PRODUCT VERSION :
javac 1.7.0_01


ADDITIONAL OS VERSION INFORMATION :
SunOS <host> 5.10 Generic_141415-07 i86pc i386 i86pc


A DESCRIPTION OF THE PROBLEM :
The following code will happily compile:

            i >>>= 4;
            s >>>= 4;

One would expect the compiler to warn you about loss-of-precision like it does if you change the code to be:

            i = i >>> 4;
            s = s >>> 4;

since, otherwise, the shift will not be unsigned. (The MSB gets a zero in integer space but this is truncated away when the value is silently converted back to a short.)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Simply compile the code supplied.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I would expect to see a loss-of-precision warning when doing the shift-assignment as well:

Foo.java:9: error: possible loss of precision in shift-assignment
            s >>>= 4;
                  ^
  required: short
  found: int
1 error
ACTUAL -
Code compiles without warning

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public class Foo
{
    public static void main(String[] args)
    {
        int i = 0xdead;
        short s = (short)i;
        do {
            i >>>= 4;
            s >>>= 4;
            System.err.println(
                String.format("0x%x", (short)i) + " " +
                String.format("0x%x", s) + " " +
                ((short)i==s)
            );
        } while (i != 0);
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Don't use ">>>=" with shorts.