Javac crashes on this program:

class F<T> {}
class C<X extends F<F<? super X>>> {
    C(X x) {
        F<? super X> f = x;
    }
}

The specification needs to be changed to resolve this issue, see 6207379.
Once the specification is clarified, the compiler should be fixed.

###@###.### 2004-12-11 00:17:12 GMT
Stack trace on 5.0u6:

The system is out of resources.
Consult the following stack trace for details.
java.lang.StackOverflowError
        at com.sun.tools.javac.code.Types.lowerBound(Types.java:112)
        at com.sun.tools.javac.code.Types$IsSubTypeFcn.visitClassType(Types.java:410)
        at com.sun.tools.javac.code.Type$ClassType.accept(Type.java:482)
        at com.sun.tools.javac.code.Types$IsSubTypeFcn.isSubType(Types.java:347)
        at com.sun.tools.javac.code.Types$IsSubTypeFcn.visitType(Types.java:387)