#13749: Panic (initTc: unresolved constraints) on some bad code -------------------------------------+------------------------------------- Reporter: uranium | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Keywords: | Operating System: Linux Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I was just refactoring some code, and partway through, before it was all compiling, I hit the below error. The code's probably just terrible in an interestingly new way; I'm pretty inexperienced at Haskell. I'll attach the file. Prelude> :r [1 of 1] Compiling Main ( /home/uranium/projects/server/src/Main.hs, interpreted ) ghc: panic! (the 'impossible' happened) (GHC version 8.0.2 for x86_64-unknown-linux): initTc: unsolved constraints WC {wc_insol = [W] get_aGsK :: t_aGsJ[tau:1] (CHoleCan: get) [W] execState_aGsX :: t_aGsW[tau:1] (CHoleCan: execState) [W] get_aGvL :: t_aGvK[tau:1] (CHoleCan: get) [W] lift_aGvU :: t_aGvT[tau:1] (CHoleCan: lift) [W] put_aGw3 :: t_aGw2[tau:1] (CHoleCan: put) [W] cellType_aGwy :: t_aGwx[tau:1] (CHoleCan: cellType) [W] insts_aGwB :: t_aGwA[tau:1] (CHoleCan: insts) [W] ports_aGwE :: t_aGwD[tau:1] (CHoleCan: ports) [W] conns_aGwH :: t_aGwG[tau:1] (CHoleCan: conns) [W] annos_aGwK :: t_aGwJ[tau:1] (CHoleCan: annos) [W] comms_aGwN :: t_aGwM[tau:1] (CHoleCan: comms)} Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13749 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler