Are there any plans to add destructors to Kotlin/native? I'm aware there is a stack overflow answer on this, but it's a year old, and things change.

we do not see enough motivation to change something here, and with weak references some usecases of destructors like figuring out if some resource no longer needed would be handled as well

Can weak references be used with a GUI toolkit/lib (eg GTK) for event handling?

what is the point of doing that?

If the event handlers close over references to GUI objects and those objects also have references to the event handlers (because they're attached to events), there is a cycle that won't be collected with pure reference counting. This used to be a big problem in JS on Internet Explorer 7 and earlier, where the DOM was based on reference-counted COM objects. So it would be nice to have the GC handle the wrapping Kotlin objects and have the destructors destroy the wrapped native objects. But maybe there is a better way, and I have my head stuck in the 90s.

Kotlin/Native can collect cyclic garbage, do you have an example where this problem actually shows up?

Hmm... I guess the kind of reference cycle I was thinking of, between Kotlin and native, isn't possible because staticCFunction can't capture any values.

It depends on how cycle appears, but if it goes via native stable pointer - you ‘re right

On the JVM side for example this is a common problem (as Henrik has mentioned earlier but in a different environment) when using JavaFX or Swing with a JVM language (eg Kotlin), hence weak references are used.