private static boolean sameModule(PsiFile file1, PsiFile file2) {
    if (file1 == file2) return true;
    if (file1 == null || file2 == null) return false;

    VirtualFile virtualFile1 = file1.getVirtualFile();
    VirtualFile virtualFile2 = file2.getVirtualFile();
    if (virtualFile1 == null || virtualFile2 == null) {
      return ComparatorUtil.equalsNullable(virtualFile1, virtualFile2);
    }

    Module module1 = ProjectRootManager.getInstance(file1.getProject()).getFileIndex().getModuleForFile(virtualFile1);
    Module module2 = ProjectRootManager.getInstance(file2.getProject()).getFileIndex().getModuleForFile(virtualFile2);

    return module1 == module2;
  }
private static boolean sameModule(PsiFile file1, PsiFile file2)