QMLLS not finding manual C++ registrations

SimpleY

The issue

I have a very basic Qt Quick App which builds and runs without issues. However importing QML modules which are manually first registered at runtime by my C++ code in main.cpp are obviously not identified by the QMLLS and therefore I get false warnings for importing the module and whenever I access something from it. This makes QML development with C++ classes/instances registered at runtime quite painful since I don't get auto-completion in the editor.

Here is Main.qml and the project structure on the left:

CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)

project(SongPlayer VERSION 0.1 LANGUAGES CXX)

set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(QT_QML_GENERATE_QMLLS_INI ON)

find_package(Qt6 6.5 REQUIRED COMPONENTS Quick)

qt_standard_project_setup(REQUIRES 6.5)

qt_add_executable(appSongPlayer
    main.cpp
)

qt_add_qml_module(appSongPlayer
    URI SongPlayer
    VERSION 1.0
    QML_FILES
        Main.qml

    SOURCES
        TestClass.h TestClass.cpp

    NO_CACHEGEN
)

# Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1.
# If you are developing for iOS or macOS you should consider setting an
# explicit, fixed bundle identifier manually though.
set_target_properties(appSongPlayer PROPERTIES
#    MACOSX_BUNDLE_GUI_IDENTIFIER com.example.appSongPlayer
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)

target_link_libraries(appSongPlayer
    PRIVATE Qt6::Quick
)

include(GNUInstallDirs)
install(TARGETS appSongPlayer
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

main.cpp:

#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "TestClass.h"

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;

    qmlRegisterSingletonInstance("MyTestModule", 1, 0, "TestInstance", new TestClass(&app));

    QObject::connect(
        &engine,
        &QQmlApplicationEngine::objectCreationFailed,
        &app,
        []() { QCoreApplication::exit(-1); },
        Qt::QueuedConnection);
    engine.loadFromModule("SongPlayer", "Main");

    return app.exec();
}

TestClass.h:

#ifndef TESTCLASS_H
#define TESTCLASS_H

#include <QObject>
#include <qqml.h>

using namespace Qt::Literals::StringLiterals;

class TestClass : public QObject
{
    Q_OBJECT

    Q_PROPERTY(QString myText READ getMyText NOTIFY myTextChanged)

public:
    explicit TestClass(QObject *parent = nullptr);

    QString getMyText() const { return u"Hello QMLSS"_s; }

signals:
    void myTextChanged();

private:
};

#endif // TESTCLASS_H

Proof those are false warnings and the app builds:

Question

What's the best way to inform the QMLLS of my module (and classes in it) if it's only registered from C++ code as seen here with qmlRegisterSingletonInstance (or in theory with QQmlContext::setContextProperty) for smooth QML development in Qt Creator?

Environment

Windows 10 64-bit
Qt Creator 14.0.2 (Community)
Qt 6.8.0
Project: Qt Quick Application, Kit: Destkop Qt 6.8.0 MinGW 64-bit with CMake

ekkescorner

instead of setContextProperty() you should use QML_SINGLETON
see: https://t1p.de/ekkeQML_SINGLETON

Axel Spoerl

Hello again :-)

Check this documentation, please.
The QML_ELEMENT macro is missing in TestClass.

SimpleY

@Axel-Spoerl Hi again too. I attempted to add QML_ELEMENT previously and that didn't help but to make sure I did not mess something up I just tried again. Here is also proof that it's not some kind of weird cache or that it gets fixed after building:
https://streamable.com/61he1v

ekkescorner

instead of setContextProperty() you should use QML_SINGLETON
see: https://t1p.de/ekkeQML_SINGLETON