#14594: 2 modules / 2500LOC takes nearly 3 minutes to build -------------------------------------+------------------------------------- Reporter: schyler | Owner: dfeuer Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): Simon, here's a tiny repro: {{{#!hs {-# language RankNTypes #-} module T14594 where import Data.Data newtype Foo = Foo (Maybe Char) gfoldlFoo :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Foo -> c Foo gfoldlFoo k z (Foo a) = z Foo `k` a }}} Compile with `-O` and `-ddump-simpl`, and search for `Data (Maybe Char)`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14594#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler