private void updateModifiersInInterface(PsiMethod newMethod) {
    LanguageLevel languageLevel = PsiUtil.getLanguageLevel(myTargetClass);
    if (JavaFeature.EXTENSION_METHODS.isSufficient(languageLevel)) {
      if (!isStatic()) {
        final PsiMethod containingMethod = PsiTreeUtil.getParentOfType(myCodeFragmentMember, PsiMethod.class, false);
        if (containingMethod != null && containingMethod.hasModifierProperty(PsiModifier.DEFAULT)) {
          if (JavaFeature.PRIVATE_INTERFACE_METHODS.isSufficient(languageLevel)) {
            PsiUtil.setModifierProperty(newMethod, PsiModifier.PRIVATE, true); // don't increase the API surface
          }
          else {
            PsiUtil.setModifierProperty(newMethod, PsiModifier.DEFAULT, true);
          }
        }
      }
      PsiUtil.setModifierProperty(newMethod, PsiModifier.PUBLIC, false);
      PsiUtil.setModifierProperty(newMethod, PsiModifier.PROTECTED, false);
      if (isStatic() || !JavaFeature.PRIVATE_INTERFACE_METHODS.isSufficient(languageLevel)) {
        PsiUtil.setModifierProperty(newMethod, PsiModifier.PRIVATE, false);
      }
    }
  }
private void updateModifiersInInterface(PsiMethod newMethod)