Проблема со сборкой проекта на QT/C++

Переделывал код, столкнулся с такой проблемой, что

C:\Kurs\ThirdWindow.cpp:21: ошибка: member access into incomplete type 'Ui::ThirdWindow' и C:\Kurs\ThirdWindow.cpp:12: ошибка: member access into incomplete type 'Ui::ThirdWindow', а так жеC:\Kurs\ThirdWindow.cpp:7: ошибка: allocation of incomplete type 'Ui::ThirdWindow'

Может кто сталкивался с таким? Помогите пожалуйста решить, вот сам код:

    #include "ThirdWindow.h"
#include "ui_ThirdWindow.h"
#include "IntListModel.h"

ThirdWindow::ThirdWindow(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::ThirdWindow)
{
    ui->setupUi(this);
    IntListModel *model = new IntListModel(this);

    ui->listView->setModel(model);
}

ThirdWindow::~ThirdWindow()
{
    delete ui;
}
void ThirdWindow::on_pushButton_clicked()
{
    ui->listView->model()->sort(0, Qt::AscendingOrder);
}

Файл ThirdWindow.h:

#ifndef THIRDWINDOW_H
#define THIRDWINDOW_H

#include <QDialog>

namespace Ui {
class ThirdWindow;
}

class ThirdWindow : public QDialog
{
    Q_OBJECT

public:
    explicit ThirdWindow(QWidget *parent = nullptr);
    ~ThirdWindow();

private slots:
    void on_pushButton_clicked();

private:
    Ui::ThirdWindow *ui;
};

#endif // THIRDWINDOW_H

qmake тоже не помог

/******************************************************************************** ** Form generated from reading UI file 'ThirdWindow.ui' ** ** Created by: Qt User Interface Compiler version 5.15.0 ** ** WARNING! All changes made in this file will be lost when recompiling UI file! ********************************************************************************/ Вот сам ui_ThirdWindow.h:

#ifndef UI_THIRDWINDOW_H
#define UI_THIRDWINDOW_H

#include <QtCore/QVariant>
#include <QtWidgets/QApplication>
#include <QtWidgets/QDialog>
#include <QtWidgets/QListView>
#include <QtWidgets/QPushButton>

QT_BEGIN_NAMESPACE

class Ui_Dialog
{
public:
    QListView *listView;
    QPushButton *pushButton;

    void setupUi(QDialog *ThirdWindow)
    {
        if (ThirdWindow->objectName().isEmpty())
            ThirdWindow->setObjectName(QString::fromUtf8("ThirdWindow"));
        ThirdWindow->resize(400, 300);
        listView = new QListView(ThirdWindow);
        listView->setObjectName(QString::fromUtf8("listView"));
        listView->setGeometry(QRect(20, 20, 361, 221));
        pushButton = new QPushButton(ThirdWindow);
        pushButton->setObjectName(QString::fromUtf8("pushButton"));
        pushButton->setGeometry(QRect(140, 250, 93, 28));

        retranslateUi(ThirdWindow);

        QMetaObject::connectSlotsByName(ThirdWindow);
    } // setupUi

    void retranslateUi(QDialog *ThirdWindow)
    {
        ThirdWindow->setWindowTitle(QCoreApplication::translate("Dialog", "Dialog", nullptr));
        pushButton->setText(QCoreApplication::translate("Dialog", "sort", nullptr));
    } // retranslateUi

};

namespace Ui {
    class Dialog: public Ui_Dialog {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_THIRDWINDOW_H

Код для ThirdWindow.ui:

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Dialog</class>
 <widget class="QDialog" name="Dialog">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>569</width>
    <height>376</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Dialog</string>
  </property>
  <widget class="QPushButton" name="pushButton">
   <property name="geometry">
    <rect>
     <x>240</x>
     <y>330</y>
     <width>75</width>
     <height>23</height>
    </rect>
   </property>
   <property name="text">
    <string>Sorting</string>
   </property>
  </widget>
  <widget class="QListView" name="listView">
   <property name="geometry">
    <rect>
     <x>40</x>
     <y>20</y>
     <width>491</width>
     <height>271</height>
    </rect>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>