#7703: GHCI crashes when loading a file, Windows 7 64 bit -------------------------------+-------------------------------------------- Reporter: crntaylor | Owner: Type: bug | Status: closed Priority: normal | Component: GHCi Version: 7.6.2 | Resolution: fixed Keywords: | Os: Windows Architecture: x86_64 (amd64) | Failure: GHCi crash Blockedby: | Blocking: Related: | -------------------------------+-------------------------------------------- Changes (by monoidal): * status: new => closed * resolution: => fixed Comment: Here's a small version: {{{ newtype O f g a = Compose { getCompose :: f (g a) } mapC :: cat a b -> cat (O g f a) (O g f b) mapC (Compose f) = mapC (mapC f) }}} GHC 7.4 and 7.6 panic, but HEAD correctly reports: {{{ cat.hs:11:7: Couldn't match kind `* -> *' with `*' When matching types t0 :: * -> * a :: * Expected type: cat a b Actual type: O (cat a0) t0 b In the pattern: Compose f In an equation for `mapC': mapC (Compose f) = mapC (mapC f) }}} (it also reports unrelated ambiguity in your code related to fundeps) I think the underlying cause is the same as #7368. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7703#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler