@NotNull
  private static Collection<VirtualFile> getFilesWithPotentialNullPassingCalls(@NotNull PsiMethod method, int parameterIndex) {
    final FileBasedIndex fileBasedIndex = FileBasedIndex.getInstance();
    final CommonProcessors.CollectProcessor<VirtualFile> collector = new CommonProcessors.CollectProcessor<>(new ArrayList<>());
    GlobalSearchScope searchScope = GlobalSearchScopeUtil.toGlobalSearchScope(method.getUseScope(), method.getProject());
    searchScope = searchScope.intersectWith(GlobalSearchScopesCore.projectProductionScope(method.getProject()));
    fileBasedIndex.getFilesWithKey(JavaNullMethodArgumentIndex.INDEX_ID,
                                   Collections.singleton(new JavaNullMethodArgumentIndex.MethodCallData(method.getName(), parameterIndex)),
                                   collector,
                                   searchScope);
    return collector.getResults();
  }
@NotNull
  private static Collection<VirtualFile> getFilesWithPotentialNullPassingCalls(@NotNull PsiMethod method, int parameterIndex)