public static Equivalence<AnnotationMirror> equivalence() {
    return ANNOTATION_MIRROR_EQUIVALENCE;
  }
Returns an {@link Equivalence} for {@link AnnotationMirror} as some implementations delegate
equality tests to {@link Object#equals} whereas the documentation explicitly states that
instance/reference equality is not the proper test.
common/src/main/java/com/google/auto/common/AnnotationMirrors.java