#12727: ghc: panic! (the 'impossible' happened) - piResultTy -------------------------------------+------------------------------------- Reporter: ocharles | 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: -------------------------------------+------------------------------------- Oddly this only happens on our build server, not on my local machine. On compilation, I get: {{{ [187 of 273] Compiling Query.Order ( Query/Order.hs, dist/build/Query/Order.o ) Query/Order.hs:340:1: warning: [-Wredundant-constraints] • Redundant constraint: MonadBaseControl IO m • In the type signature for: updateOrdersSuccess :: (MonadBaseControl IO m, MonadTransaction m) => m () ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): piResultTy Maybe Int64 a1_a4WiL Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} The configuration parameters are: {{{ configureFlags: --verbose --prefix=/nix/store /qxfjd5jxr593dn43i3659s86d0rdllyv-circuithub-api-0.0.4 --libdir=$prefix/lib/$compiler --libsubdir=$pkgid --with-gcc=gcc --package-db=/tmp/nix-build-circuithub-api-0.0.4.drv-0/package.conf.d --ghc-option=-j1 --disable-split-objs --disable-library-profiling --disable-profiling --disable-shared --enable-library-vanilla --disable- executable-dynamic --disable-tests }}} I've attached Query/Order.hs, but you won't be able to compile it stand- alone. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12727 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler