Unsafe Functions

I would like to start a discussion on the role of unsafe functions in 
Haskell:

  unsafePerformIO :: IO a -> a
  unsafeInterleaveIO :: IO a -> IO a
  unsafeInterleaveST :: ST s a -> ST s a
  unsafeIOToST :: IO a -> ST s a
  unsafeIOToSTM :: IO a -> STM a
  unsafeFreeze, unsafeThaw,
  unsafePreservingMatrix, unsafeRenderPrimitive

perhaps also

  unsafeForeignPtrToPtr :: ForeignPtr a -> Ptr a
    (which is already under Foreign.*)
  hGetContents :: Handle -> IO String
    (which is lazy rather than unsafe per se)

* Do you use these, and what for?

* Is there safe functionality that can currently only be obtained with them?

* Do you think they should be standardised, and how?

I'm thinking the unsafe functions should be moved from System.IO.Unsafe 
and elsewhere to Unsafe, similar to Foreign.*, to better separate them 
from "real Haskell" conceptually. Also, I would add:

  unsafeCoerce :: a -> b

--
Ashley Yakeley, Seattle WA
WWEWDD? http://www.cs.utexas.edu/users/EWD/