#12168: panic! (the 'impossible' happened) with gi-gtk 3.0.4 -------------------------------------+------------------------------------- Reporter: drb226 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I'm able to get two different panics, depending on how I try to build gi- gtk. Firstly, on my mac: {{{ brew install gtk+3 stack unpack gi-gtk-3.0.4 cd gi-gtk-3.0.4 stack init --resolver nightly-2016-06-08 PKG_CONFIG_PATH=/usr/local/opt/libffi/lib/pkgconfig/ stack build }}} This results in {{{ [650 of 650] Compiling GI.Gtk ( GI/Gtk.hs, .stack- work/dist/x86_64-osx/Cabal-1.24.0.0/build/GI/Gtk.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-apple-darwin): RnEnv.plusAvail bindingSignalWriteNext CheckButtonK{CheckButtonK} }}} Secondly, also on my mac, but within an ubuntu-based docker image: {{{ docker run -it snoyberg/stackage:nightly cd ~ stack unpack gi-gtk-3.0.4 cd gi-gtk-3.0.4 stack init --resolver nightly-2016-06-08 stack build }}} This results in {{{ [599 of 654] Compiling GI.Gtk.Objects.Widget ( GI/Gtk/Objects/Widget.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/GI/Gtk/Objects/Widget.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): urk! lookup local fingerprint $fAttrInfoWidgetMarginTopPropertyInfo4 }}} The latter panic was first observed on the stackage build server, during the June 8th nightly build. That's why, to use the same dependencies, I specified the nightly-2016-06-08 stack resolver in order to reproduce it. I originally recorded it here: https://github.com/fpco/stackage/issues/1569 -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12168 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler