Ошибка при сборке проекта - invalid use of non-static data member 'MainWindow::test'

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include "hidapi.h"
#include "ui_mainwindow.h"
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    QLineEdit* test;
    ~MainWindow();
    void SetTextToLineEdit(QLineEdit* LineEditName, QString Text);
 
private:
    Ui::MainWindow *ui;
};
 
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QLineEdit* test;// = ui->lineEdit;
}
 
void SetTextToLineEdit(QLineEdit* test, QString Text)
{
    test->setText(Text);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}

#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QtCore>
 
 
class MyThread : public QThread
{
public:
    MyThread();
    void run();
    ~MyThread();
};
 
#endif // MYTHREAD_H

#include "mythread.h"
#include <mainwindow.h>
#include <ui_mainwindow.h>
 
 
MyThread::MyThread()
{
 
}
 
void MyThread::run()
{
    MainWindow::SetTextToLineEdit(MainWindow::test,"123");
}
 
MyThread::~MyThread()
{
 
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    test = ui->lineEdit;
}
//ThreadAutorisation thread;
 
void SetTextToLineEdit(QLineEdit* test, QString Text)
{
    test->setText(Text);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}

public:
...
    QLineEdit* test;
...
    void SetTextToLineEdit(QLineEdit* LineEditName, QString Text);

#include "mythread.h"
//#include <QtCore>
#include <mainwindow.h>
#include <ui_mainwindow.h>
 
 
MyThread::MyThread()
{
 
}
 
void MyThread::run()
{
    //MainWindow* mw = new MainWindow;
    SetTextToLineEdit(test,"123");
}
 
MyThread::~MyThread()
{
 
}

'test' was not declared in this scope
'SetTextToLineEdit' was not declared in this scope

    SetTextToLineEdit(test,"123");

/home/gorbag/Qt5.4.1/5.4/gcc/include/QtCore/qobject.h:220: ошибка: invalid application of 'sizeof' to incomplete type 'QStaticAssertFailure<false>'

Q_STATIC_ASSERT_X(QtPrivate::HasQ_OBJECT_Macro<typename SignalType::Object>::Value,
                          "No Q_OBJECT in the class with the signal");