@Override
      public void visitReferenceElement(@NotNull PsiJavaCodeReferenceElement reference) {
        final PsiElement parent = reference.getParent();
        if (!(parent instanceof PsiReferenceList)) return;
        final PsiElement grandParent = parent.getParent();
        if (!(grandParent instanceof PsiClass)) return;
        if (reference.isReferenceTo(aClass)) {
          subclasses.add((PsiClass)grandParent);
        }
      }
@Override
      public void visitReferenceElement(@NotNull PsiJavaCodeReferenceElement reference)