When I use a .ui file in a QT Custom Designer Widget project, crashed and exit, why?

[qtaihaozhe]

ui->setupUi(this);

Here is the code
CMakeLists.txt:
cmake_minimum_required(VERSION 3.16)

project(MyCtrl LANGUAGES CXX)

add_library(MyCtrl SHARED myctrl.h myctrl.cpp myctrlplugin.h myctrlplugin.cpp myctrl.ui)

if(NOT DEFINED QT_DESIGNER_PLUGIN_DIR)
set(QT_DESIGNER_PLUGIN_DIR "C:\Qt\6.5.3\mingw_64\plugins\designer")
endif()
message(STATUS "QT_DESIGNER_PLUGIN_DIR: ${QT_DESIGNER_PLUGIN_DIR}")

set_target_properties(MyCtrl PROPERTIES
CXX_STANDARD 11
CXX_STANDARD_REQUIRED ON
AUTOMOC ON
AUTOUIC ON
AUTORCC ON
)

find_package(Qt6 COMPONENTS Core Gui Widgets Designer REQUIRED)

target_compile_definitions(MyCtrl PRIVATE MYPLUGIN_LIBRARY)
target_link_libraries(MyCtrl PRIVATE Qt6::Core Qt6::Gui Qt6::Widgets Qt6::Designer)

Qt Designer plugins dir

set_target_properties(MyCtrl PROPERTIES
ARCHIVE_OUTPUT_DIRECTORY_DEBUG ${QT_DESIGNER_PLUGIN_DIR}
RUNTIME_OUTPUT_DIRECTORY_DEBUG ${QT_DESIGNER_PLUGIN_DIR}
)

---

myctrl.h

#ifndef MYCTRL_H
#define MYCTRL_H

#include <QWidget>
#include "ui_myctrl.h"
#include "exports.h"

namespace Ui
{

class MyCtrl;

}

class MYPLUGIN_EXPORT MyCtrl : public QWidget
{
Q_OBJECT

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

private:
Ui::MyCtrl *ui;
};

#endif // MYCTRL_H

myctrl.cpp
#include "myctrl.h"

MyCtrl::MyCtrl(QWidget *parent) : QWidget(parent)
{
// ui->setupUi(this);
}

MyCtrl::~MyCtrl()
{
delete ui;
}

[qtaihaozhe]

If copy the dll file to designer plugin dir, designer.exe can not start.

[qtaihaozhe]

I have found the error:
CoordinateInput::CoordinateInput(QWidget *parent) : QWidget(parent),
ui(new Ui::CoordinateInput)
I lost ",ui(new Ui::CoordinateInput)".

[Axel Spoerl]

Great that you found the solution.
Question: How did it happen? Did uic produce broken C++ code?
Remark: Please use the </> tags to format your code. Makes it so much easier for others to read.