#14752: Unboxed sums documentation looks wrong -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.2 Component: Documentation | Version: 8.2.2 Resolution: | Keywords: UnboxedSums Operating System: Unknown/Multiple | Architecture: Type of failure: Documentation | Unknown/Multiple bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): If you generate STG and Cmm for this program: {{{ {-# LANGUAGE UnboxedSums, UnboxedTuples, MagicHash #-} module Lib where type UnboxedBool = (# (# #) | (# #) #) unboxBool :: Bool -> UnboxedBool unboxBool True = (# (# #) | #) unboxBool False = (# | (# #) #) boxBool :: UnboxedBool -> Bool boxBool (# (# #) | #) = True boxBool (# | (# #) #) = False }}} you'll see that `UnboxedBool` is clearly represented as single integer. In your program, I don't understand why you expect your `Bool` to be unboxed. You can put bottom values in unboxed tuples/sums so everything seems fine here. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14752#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler