#8447: A combination of type-level comparison and subtraction does not work for 0 -------------------------------------+------------------------------------- Reporter: nushio | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler (Type | Version: 7.6.3 checker) | Operating System: Linux Keywords: | Type of failure: GHC rejects Architecture: Unknown/Multiple | valid program Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- The following function on type level naturals {{{ Diff x y = If (x <=? y) (y-x) (x-y) }}} does not work when either x or y is 0. https://github.com/nushio3/practice/blob/ea8a1716b1d6221ce32d77432b6de3f38e6... /type-nats/int-bug.hs I've tested this code on ghc 7.7.20130926 since I couldn't build the really latest ghc. I'm sorry if it is already fixed on the ghc head. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8447 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler