private static boolean hasNullContract(@NotNull PsiModifierListOwner owner) {
    if (owner instanceof PsiParameter parameter && parameter.getDeclarationScope() instanceof PsiMethod method) {
      int index = method.getParameterList().getParameterIndex(parameter);
      List<StandardMethodContract> contracts = JavaMethodContractUtil.getMethodContracts(method);
      return ContainerUtil.exists(contracts, 
                               c -> c.getParameterConstraint(index) == StandardMethodContract.ValueConstraint.NULL_VALUE);
    }
    return false;
  }
private static boolean hasNullContract(@NotNull PsiModifierListOwner owner)