private void collectConflicts(@NotNull MultiMap<PsiElement, @DialogMessage String> conflicts,
                                @NotNull Ref<UsageInfo[]> refUsages) {
    for (VirtualFile vFile : myFilesToMove.keySet()) {
      PsiFile file = myManager.findFile(vFile);
      if (file == null) continue;
      try {
        myFilesToMove.get(vFile).checkMove(file);
      }
      catch (IncorrectOperationException e) {
        conflicts.putValue(file, e.getMessage());
      }
    }
    for (MoveDirectoryWithClassesHelper helper : MoveDirectoryWithClassesHelper.findAll()) {
      helper.preprocessUsages(myProject, getPsiFiles(), refUsages.get(), myTargetDirectory, conflicts);
    }
  }
private void collectConflicts(@NotNull MultiMap<PsiElement, @DialogMessage String> conflicts,
                                @NotNull Ref<UsageInfo[]> refUsages)