Respectfully, it is important to understand whether sort stability is as bug or not. Particularly since you seem to have experienced exceptions on Android, and assuming that the problem was in the sort stability may have mislead you.

It's still reproducible just by substituting the top function for the stable alternative we use: http://pastebin.com/D3S6SYBM. Haxe 3.1.3 on OSX.

Do you have the same problem with a deterministic comparison function?

I'm not dismissing the existence of a bug just because of this (although the issue may be related to it), but non-deterministic comparison functions are problematic with many sort _algorithms_. You might experience (other) problems when using implementation independent "sort" APIs, since many algorithms need to rerun the comparison function several times and expect consistent behaviour; I would expect certain algorithms to, for instance, never complete.

The haxe people are the ones you need to discuss it further with. My pastebin expires in a week so you might want to clone it before you link to it.

Hm... No.

I don't want to attach myself to further discussion of it, but it is still a crash reasonably isolated to their standard library and I took the time to document it so that my feedback could be helpful. If you don't pass it on they will miss this opportunity to improve their platform.