@Nullable
  private @NlsContexts.DialogMessage String validateInputData() {
    final PsiManager manager = PsiManager.getInstance(myProject);
    final String fqName = getTargetClassName();
    if (fqName != null && fqName.isEmpty()) {
      return RefactoringBundle.message("no.destination.class.specified");
    }
    else {
      if (!PsiNameHelper.getInstance(manager.getProject()).isQualifiedName(fqName)) {
        return RefactoringBundle.message("0.is.not.a.legal.fq.name", fqName);
      }
      else {
        RecentsManager.getInstance(myProject).registerRecentEntry(RECENTS_KEY, fqName);
        final PsiClass[] targetClass = new PsiClass[]{null};
        CommandProcessor.getInstance().executeCommand(myProject, () -> {
          try {
            targetClass[0] = findOrCreateTargetClass(manager, fqName);
          }
          catch (IncorrectOperationException e) {
            CommonRefactoringUtil.showErrorMessage(
              MoveMembersImpl.getRefactoringName(),
              e.getMessage(),
              HelpID.MOVE_MEMBERS,
              myProject);
          }
        }, RefactoringBundle.message("create.class.command", fqName), null);

        if (targetClass[0] == null) {
          return "";
        }

        if (mySourceClass.equals(targetClass[0])) {
          return RefactoringBundle.message("source.and.destination.classes.should.be.different");
        } else if (!mySourceClass.getLanguage().equals(targetClass[0].getLanguage())) {
          return RefactoringBundle.message("move.to.different.language", UsageViewUtil.getType(mySourceClass), mySourceClass.getQualifiedName(), targetClass[0].getQualifiedName());
        }
        else {
          for (MemberInfo info : myMemberInfos) {
            if (!info.isChecked()) continue;
            if (PsiTreeUtil.isAncestor(info.getMember(), targetClass[0], false)) {
              return JavaRefactoringBundle.message("cannot.move.inner.class.0.into.itself", info.getDisplayName());
            }
          }

          if (!targetClass[0].isWritable()) {
            CommonRefactoringUtil.checkReadOnlyStatus(myProject, targetClass[0]);
            return "";
          }

          return null;
        }
      }
    }
  }
@Nullable
  private @NlsContexts.DialogMessage String validateInputData()