#8777: Ghc crashes when compiling happstack-server on ubuntu-docker ------------------------------------+------------------------------------- Reporter: timthelion | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.4.1 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I am trying to install a package that requires happstack on docker. I recieved the following error: {{{ src/Happstack/Server/Internal/Socket.hs:61:7:ghc: panic! (the 'impossible' happened) (GHC version 7.4.1 for x86_64-unknown-linux): Can't happen: pprExp (CompExp []) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} It appears I am not the first to receive this error as I found the following paste on lpaste: http://lpaste.net/report/99343 This bug is hard to reproduce. I tried making a minimal case for it in which only haskell-platform was installed. In the minimal case, ghc DOES NOT crash. This works: {{{ FROM ubuntu RUN apt-get update RUN apt-get install -y haskell-platform RUN cabal update RUN cabal install --global happstack-server-7.3.3 }}} However, if you run the following docker file, ghc will crash: {{{ FROM ubuntu RUN apt-get update RUN apt-get install -y haskell-platform git libghc-terminfo-dev libghc- haskeline-dev RUN cabal update RUN git clone --branch dev https://github.com/evancz/Elm.git RUN git clone --branch dev https://github.com/evancz/elm-repl.git RUN git clone https://github.com/evancz/elm-get.git RUN cd Elm; git checkout a815b2fbd00e76c0109b1ab916fe5d0eb184648c RUN cd elm-repl; git checkout 6ab74981363e8e7fabc05083539891568e3c4f17 RUN cd elm-get ; git checkout c67a8ba285f6bfde0a520da1552c4c3443cfab8e RUN cabal install --global Elm elm-repl elm-get Elm/server }}} Crashes with attached output. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8777 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler