#12732: GHC bug -------------------------------------+------------------------------------- Reporter: Iceland_jack | 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: -------------------------------------+------------------------------------- A frog told me about this {{{#!hs (a ... b) xs | a == x , (l, _:r) <- break (== x) xs = l ++ [x] }}} {{{ baldur@Loki:~$ ghci -fobject-code -fdefer-typed-holes -ignore-dot-ghci /tmp/tnVL.hs GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Main ( /tmp/tnVL.hs, /tmp/tnVL.o ) /tmp/tnVL.hs:2:10: warning: [-Wtyped-holes] Variable not in scope: x /tmp/tnVL.hs:3:27: warning: [-Wtyped-holes] Variable not in scope: x /tmp/tnVL.hs:4:11: warning: [-Wtyped-holes] Variable not in scope: x ghc: panic! (the 'impossible' happened) (GHC version 8.0.1 for x86_64-unknown-linux): StgCmmEnv: variable not found $dEq_a26w local binds for: $trModule $trModule1_r29y $trModule2_r2a9 x_r2aa x1_r2ab x2_r2ac a2_s2ah b_s2ai xs_s2aj fail_s2ak Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}} I managed to find a more minimal example {{{#!hs u a | a == x = undefined }}} doesn't trigger error in GHCi. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12732 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler