Question

Xcode raising “incompatible pointer types sending ‘subclassA’ to parameter of type ‘subclassB’ ” warning. Compiling with clang.

In the case where the warning is raised, I use a

[subclassA isKindOfClass: [subclassB class]] ... 

to ensure compatible pointer use. I’d like something like:

    #pragma clang diagnostic push
    #pragma clang diagnostic ignored "-Warc-performSelector-leaks"
    // warning-raising code
    #pragma clang diagnostic pop

but for the appropriate warning raised. I.e. Whats the clang flag to ignore the specified diagnostic?

Thanks for your time.

Answer 1

If I understand you right, you’re saying something like

if ([subclassA isKindOfClass:[subclassB class]]) {
    [foo someMethodThatWantsSubclassB:subclassA];
}

The fix here is to cast subclassA after the successful type assertion. Your case is a bit odd in that you’re dynamically determining the type of subclassB instead of testing for a static type, but in the method -someMethodThatWantsSubclassB: you definitely know the type involved, so you’d write something like

if ([subclassA isKindOfClass:[subclassB class]]) {
    [foo someMethodThatWantsSubclassB:(BClass)subclassA];
}

If you have some really weird setup where you don’t actually know the static type of subclassB (although I can’t imagine the situation here) you could simply cast to (id) instead to get rid of the warning:

if ([subclassA isKindOfClass:[subclassB class]]) {
    [foo someMethodThatWantsSubclassB:(id)subclassA];
}