(== <literal>) not matching in rules

[Donald Bruce Stewart]

With the new liberalised rule syntax, I can write:

    {-# RULES
        "FPS specialise break (x==)" forall x.
            break (x==) = breakByte x
        "FPS specialise break (==x)" forall x.
            break (==x) = breakByte x
      #-}

Which is very useful (Data.ByteString can detect these an substitute in a
memchr, must faster). The following works nicely:

    import qualified Data.ByteString as P
    main = do
        ps <- P.getContents
        print $ P.break (==c) ps
    c = 50

3 RuleFired
    1 FPS specialise break (==x)
    1 int2Word#
    1 narrow8Word#

However, if I inline the constant, the rule refuses to fire:

    import qualified Data.ByteString as P
    main = do
        ps <- P.getContents
        print $ P.break (==50) ps

    2 RuleFired
        1 int2Word#
        1 narrow8Word#

Rewriting without sections and it still fails:

    import qualified Data.ByteString as P
    main = do
        ps <- P.getContents
        print $ P.break ((==) 50) ps

The Core looks like:
    print_a13O (Data.ByteString.break (==_a1tG lit_a1tF) ps_aBu))

    ==_a1tG :: GHC.Word.Word8 -> GHC.Word.Word8 -> GHC.Base.Bool
    ==_a1tG = GHC.Base.== @ GHC.Word.Word8 (GHC.Num.$p1Num @ GHC.Word.Word8 GHC.Word.$f37)    

Could this funny ==_a1tG be getting in the way?

This is with today's HEAD including the ByteString patches I just pushed:
    Thu Aug 24 11:26:11 EST 2006  Don Stewart <dons at cse.unsw.edu.au>
  * Add spec rules for sections in Data.ByteString

-- Don