Unexpected behavior of unsafeCoerce converting Word32 to Word8

The function unsafeCoerce behaves unexpected if it is used to convert Word32 to Word8:

main = do
  -- prints 135
  print (fromIntegral (1234567 :: Word32) :: Word8)

  -- prints 1234567
  print (unsafeCoerce (1234567 :: Word32) :: Word8)

On the other hand coercing Ptr Word32 to Ptr Word8 or the other way around works perfectly fine.

Trac metadata

Trac field	Value
Version	7.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
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changed weight to 5

added Tbug Trac import labels

closed

GHC gives no guarantees for this case: http://hackage.haskell.org/package/ghc-prim-0.3.1.0/docs/GHC-Prim.html#v:unsafeCoerce-35- since Word32 and Word8 are boxed types.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedInvalid

added incorrect runtime result label

added Pnormal label