This is not a good idea. It hides the return in the other lines, making the function less readable, the user won't know if the function returns there unless they look at the macro.
And performance wise a macro is useless, its contents get pasted into its declarations while compiling. At the end, it just makes the code less readable. Readability is very important. But I do have to admit that this function is not very clean. Maybe using lambdas might make it cleaner, it does go in a similar direction as your macro

You could do something like this:

auto notifyAndClear = [this](TextID id) {
 OSDExtras::Notify(id, Color::Red);
 this->ClearPlayerMessage();
};

And then just do:

if (!IDList::AnimationValid(animID, GetPlayerIndex())) {
 return notifyAndClear(TextID::CHAT_INVALID_ANIMATION);
}

This would make it clear what is happening

Understood, no disgustingly ugly macro definitions allowed here 👍
tbh, I thought the macro was ugly too but I didn't want to have duplicate code. A lambda indeed seems more like a c++ism. Thanks.

I am guessing this was by accident? Should be return true;

Yep that’s a mistake 😓