class InstanceFromStatic<T> {
    class Inner {}

    static void m(Inner i) {} // expected: error; actual: error

    static class Child extends Inner { // expected: error; actual: nothing
        Child() { new InstanceFromStatic().super(); }
    }
}

InstanceFromStatic.java:5: error: non-static class InstanceFromStatic.Inner cannot be referenced from a static context
    static void m(Inner i) {}
                  ^
InstanceFromStatic.java:8: warning: [unchecked] unchecked conversion
        Child() { new InstanceFromStatic().super(); }
                  ^
  required: InstanceFromStatic<T>
  found: InstanceFromStatic
  where T is a type-variable:
    T extends Object declared in class InstanceFromStatic

Because the outer class is generic, references to the non-static instance class Inner are treated as if they were references to InstanceFromStatic<T>.Inner. Since T cannot be referenced from a static context, this should be an error. javac detects the error in most cases, but fails to do so in the 'extends' clause of a static nested class; an unchecked conversion to InstanceFromStatic<T> is then performed in order to provide the enclosing instance (even though T is undefined in this context).

Note that, if InstanceFromStatic is not generic, none of this is a problem, and the program (correctly) compiles without error.

I tried to find the spec for this check, and wasn't able to turn anything up. It's possible there needs to be a corresponding spec clarification.

This is a regression beginning with 7: javac 6u65 reports two errors, as expected.