Transfer INLINE to specialised functions
When the Specialise pass generates a specialised copy of a function,
it should transfer the INLINE information to the specialised function.
Otherwise, whether or not the INLNE happens can depend on whether
specialisation happens, which seems wrong. See Note [Inline specialisation]
in Specialise.lhs
Here's the example Roman reported
primWriteMU :: UAE e => MUArr e s -> Int -> e -> ST s ()
{-# INLINE primWriteMU #-}
primWriteMU = writeMBU . unMUAPrim
------
The problem is that primWriteMU doesn't get inlined *sometimes*, which
results in code like
case Data.Array.Parallel.Unlifted.Flat.UArr.$sprimWriteMU
@ s11_X1nJ
marr_s25s
(GHC.Base.I# sc_s27F)
GHC.Base.False
new_s_a1Db
of wild3_a1Dd { (# new_s1_X1F9, r_a1Dc #) -> ...
Note the fact that we have a call to the *specialised* $sprimWriteMU.