Warnings for QKeyCombination deprecation after Qt6

[just-ero]

Hi, I'm working on some warnings in our codebase.

I'm now at the following code:

auto keys = Qt::Key_R | Qt::CTRL | Qt::ALT;
//                            warning: ^~~

Here, I get the following warning:

‘constexpr QKeyCombination::operator int() const’ is deprecated: Use QKeyCombination instead of int

The warning disappears for the following two variants:

auto keys = Qt::Key_R | Qt::ALT;

auto keys = Qt::CTRL | Qt::ALT | Qt::Key_R;

What's causing the warning here? How should I use QKeyCombination correctly?

[just-ero]

It wasn't really clear to me that using Qt::CTRL | Qt::ALT is still part of the usage. With that, the problem makes a lot more sense.

Qt::Key_R | Qt::CTRL | Qt::ALT evaluates to (Qt::Key_R | Qt::CTRL) | Qt::ALT, which results in QKeyCombination | Qt::ALT, which is what's raising the warning, since QKeyCombination does not have any (non-deprecated) operators itself.

Qt::CTRL | Qt::ALT | Qt::Key_R instead evaluates to (Qt::CTRL | Qt::ALT) | Qt::Key_R, which results in Qt::Modifiers | Qt::Key_R, which is an operation that is defined.

This is kinda the answer I was looking for.

[Christian Ehrlicher]

See https://doc.qt.io/qt-6/qkeycombination.html#QKeyCombination-1

[just-ero]

@Christian-Ehrlicher
I would not be making this post if I understood what that page is telling me.

[JonB]

@just-ero
I have not used this, but isn't @Christian-Ehrlicher telling you from the linked method to keep the modifiers separate from the key? So:

QKeyCombination(Qt::CTRL | Qt::ALT, Qt::Key_R)

?

[Christian Ehrlicher]

Just use this ctor and pass your key and modifiers - what else to say?

[just-ero]

It wasn't really clear to me that using Qt::CTRL | Qt::ALT is still part of the usage. With that, the problem makes a lot more sense.

Qt::Key_R | Qt::CTRL | Qt::ALT evaluates to (Qt::Key_R | Qt::CTRL) | Qt::ALT, which results in QKeyCombination | Qt::ALT, which is what's raising the warning, since QKeyCombination does not have any (non-deprecated) operators itself.

Qt::CTRL | Qt::ALT | Qt::Key_R instead evaluates to (Qt::CTRL | Qt::ALT) | Qt::Key_R, which results in Qt::Modifiers | Qt::Key_R, which is an operation that is defined.

This is kinda the answer I was looking for.