Generalize makeStableName#

The function makeStableName# has the following type:

makeStableName# :: a -> State# RealWorld -> (#State# RealWorld, StableName# a#)

I believe that it could safely be changed to:

makeStableName# :: a -> State# s -> (#State# s, StableName# a#)

Currently, I have some code that looks like this:

{-# LANGUAGE MagicHash #-}
{-# LANGUAGE UnboxedTuples #-}
module Example
  ( Stable
  , stabilize
  , destabilize
  ) where

import GHC.Prim
import GHC.ST

data Stable s a = Stable (StableName# a) a

stabilize :: a -> ST s (Stable s a)
stabilize a = ST $ \ s ->
  case makeStableName# a (unsafeCoerce# s) of (# s', sn #) -> (# unsafeCoerce# s', Stable sn a #)

destabilize :: Stable s a -> a
destabilize (Stable _ a) = a

instance Eq a => Eq (Stable s a) where
  Stable sn1 a1 == Stable sn2 a2 = case eqStableName# sn1 sn2 of
    0# -> a1 == a2
    _  -> True

I want to be working in ST, not in IO, and I believe that this use of unsafeCoerce# is safe. However, it would be nice to not have to use it at all.