I would very much like to see this fixed.

Yes, it can make some extension types immortal, but I believe those types were relying on buggy behavior, and need to be fixed to prevent memory leaks.

I think this is a big enough change to be mentioned in What’s New.


> Any ideas for reducing the chance of breakage or increasing the chance of detecting it in user code would help.

I'd recommend that all C extensions have leak detection as part of their test suite. I don't think we can do much better :(

> leaking types is unlikely to have a big enough memory impact in most application to be easily detected.

Indeed, it's not a big enough problem in most applications.