Confusing error message for method conflict

The error message for incompatible inherited methods doesn't account for the possibility that both methods could come from the same class. The message could be improved:

InstanceClash.java:13: error: types Foo<String> and Foo<String> are incompatible; both define m(java.lang.String), but with unrelated return types
  interface I extends Foo<String> {}
  ^
Here's the relevant source:

  public static interface Foo<S> {
    String m(String s);
    int m(S o);
  }

  interface I extends Foo<String> {}