#11172: Turning on optimisations produces Impossible case alternative -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Runtime crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): I'd like to reproduce, but I get this (with the current HEAD). Any suggestions, anyone? {{{ bash$ cabal install --with-ghc=/home/simonpj/5builds/HEAD-4/inplace/bin /ghc-stage2 Resolving dependencies... cabal: Could not resolve dependencies: trying: impossible-case-alternative-repro-0.0 (user goal) trying: base-4.9.0.0/installed-4.9... (dependency of impossible-case-alternative-repro-0.0) trying: either-4.4.1 (dependency of impossible-case-alternative-repro-0.0) trying: semigroupoids-5.0.0.4 (dependency of either-4.4.1) trying: semigroupoids-5.0.0.4:+tagged trying: semigroupoids-5.0.0.4:+comonad trying: comonad-4.2.7.2 (dependency of semigroupoids-5.0.0.4:+comonad) trying: comonad-4.2.7.2:+distributive trying: comonad-4.2.7.2:+contravariant trying: contravariant-1.3.3 (dependency of comonad-4.2.7.2:+contravariant) trying: void-0.7.1 (dependency of contravariant-1.3.3) next goal: hashable (dependency of void-0.7.1) rejecting: hashable-1.2.3.3, 1.2.3.2 (conflict: base==4.9.0.0/installed-4.9..., hashable => base>=4.0 && <4.9) rejecting: hashable-1.2.3.1, 1.2.3.0, 1.2.2.0, 1.2.1.0, 1.2.0.10, 1.2.0.9, 1.2.0.8, 1.2.0.7, 1.2.0.6, 1.2.0.5, 1.2.0.4, 1.2.0.3, 1.2.0.2, 1.2.0.1, 1.2.0.0, 1.1.2.5, 1.1.2.4, 1.1.2.3 (conflict: base==4.9.0.0/installed-4.9..., hashable => base>=4.0 && <4.8) rejecting: hashable-1.1.2.2, 1.1.2.1, 1.1.2.0, 1.1.1.0, 1.1.0.0 (conflict: base => ghc-prim==0.5.0.0/installed-0.5..., hashable => ghc-prim<0.3) rejecting: hashable-1.0.1.1, 1.0.1.0, 1.0.0 (conflict: void => hashable>=1.1) Dependency tree exhaustively searched. }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11172#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler