Test IORef identity?

Question

In Haskell, is there a way to test whether two IORefs are identical? I'm looking for something like this:

IORef a -> IORef a -> IO Bool

This would be useful if you want to visualize a graph made of IORefs, for example. I don't think it would break referential transparency, because IORefs have a meaningful identity (and the result could be in IO, anyway). And I assume it wouldn't be hard to implement this efficiently, as a pointer comparison.

Is this available somewhere? Or if not, why not?

(Edit: I just found System.Mem.StableName from a different SO question, which looks helpful.)

Answer 1

Don't overthink it. You have instance Eq (IORef a), so you can just use ==, and the result isn't even in IO.