NewDeleteLeaks false positive calling QTimer::singleShot with a lambda function

[llvmbot]

Bugzilla Link	40367
Version	unspecified
OS	Linux
Attachments	Minimal example showing false positive of NewDeleteLeaks check
Reporter	LLVM Bugzilla Contributor
CC	@devincoughlin,@EugeneZelenko

Extended Description

The NewDeleteLeaks check thinks that QTimer::singleShot leaks the lambda function object, but internally Qt reference counts the object and takes care of deleting it.

The attached QtSingleShotNewDeleteLeakFalsePositive.cpp file demonstrates the error:

/usr/include/x86_64-linux-gnu/qt5/QtCore/qtimer.h:154:5: error: Potential memory leak [clang-analyzer-cplusplus.NewDeleteLeaks,-warnings-as-errors]
}
^
/home/.../QtSingleShotNewDeleteLeakFalsePositive.cpp:5:5: note: Calling 'QTimer::singleShot'
QTimer::singleShot(0, [=] {});
^
/usr/include/x86_64-linux-gnu/qt5/QtCore/qtimer.h:125:9: note: Calling 'QTimer::singleShot'
singleShot(interval, defaultTypeFor(interval), nullptr, slot);
^
/usr/include/x86_64-linux-gnu/qt5/QtCore/qtimer.h:152:24: note: Memory is allocated
new QtPrivate::QFunctorSlotObject<Func1, 0,
^
/usr/include/x86_64-linux-gnu/qt5/QtCore/qtimer.h:154:5: note: Potential memory leak
}
^

This is with Qt 5.9.5 on Ubuntu 18.04. I do not see the issue on Windows with the same Qt version.

[llvmbot]

assigned to @devincoughlin