Serious typo in IntMap.hs

Someone has recently (since 6.8.3) taken a "style" pass over IntMap.hs. Apparently they didn't like reusing identifiers in different scopes, so they changed this function (at the very core of IntMap) from this

highestBitMask :: Nat -> Nat
highestBitMask x
  = case (x .|. shiftRL x 1) of 
     x -> case (x .|. shiftRL x 2) of 
      x -> case (x .|. shiftRL x 4) of 
       x -> case (x .|. shiftRL x 8) of 
        x -> case (x .|. shiftRL x 16) of 
         x -> case (x .|. shiftRL x 32) of   -- for 64 bit platforms
          x -> (x `xor` (shiftRL x 1))

to this

highestBitMask :: Nat -> Nat
highestBitMask x0
  = case (x0 .|. shiftRL x0 1) of
     x1 -> case (x1 .|. shiftRL x1 2) of
      x2 -> case (x2 .|. shiftRL x2 4) of
       x3 -> case (x3 .|. shiftRL x3 8) of
        x4 -> case (x3 .|. shiftRL x4 16) of
         x5 -> case (x4 .|. shiftRL x5 32) of   -- for 64 bit platforms
          x6 -> (x6 `xor` (shiftRL x6 1))

If you stare at it long enough, you might find the typo. Don't cheat and look at the patch. I'll give you a hint: quickcheck won't find it because the tests don't use big enough integers.

Needless to say this completely breaks the library, and if it ain't broke... :)

Trac metadata

Trac field	Value
Version	6.8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	libraries (other)
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