private @Nls @Nullable String getUpdateErrorMessage(ProjectFileIndex fileIndex, Object selectedItem) {
    if (myInitialTargetDirectory != null && selectedItem instanceof DirectoryChooser.ItemWrapper && selectedItem !=
                                                                                                    DirectoryChooser.ItemWrapper.NULL) {
      final PsiDirectory directory = ((DirectoryChooser.ItemWrapper)selectedItem).getDirectory();
      final boolean isSelectionInTestSourceContent = fileIndex.isInTestSourceContent(directory.getVirtualFile());
      final boolean inTestSourceContent = fileIndex.isInTestSourceContent(myInitialTargetDirectory.getVirtualFile());
      if (isSelectionInTestSourceContent != inTestSourceContent) {
        if (inTestSourceContent && reportBaseInTestSelectionInSource()) {
          return JavaBundle.message("destination.combo.source.root.not.expected.conflict");
        }
        if (isSelectionInTestSourceContent && reportBaseInSourceSelectionInTest()) {
          return JavaBundle.message("destination.combo.test.root.not.expected.conflict");
        }
      }
    }
    return null;
  }
private @Nls @Nullable String getUpdateErrorMessage(ProjectFileIndex fileIndex, Object selectedItem)