#10426: matchGroupArity panic with PatternSynonyms ---------------------------------------+--------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.1 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | ---------------------------------------+--------------------------------- {{{#!hs {-# LANGUAGE PatternSynonyms, ViewPatterns, EmptyCase #-} pattern Id <- (id -> _) where }}} which gives: {{{#!hs % ghc -ignore-dot-ghci tmp.FbbzjZ48OO.hs [1 of 1] Compiling Main ( tmp.FbbzjZ48OO.hs, tmp.FbbzjZ48OO.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.10.0.20150316 for i386-unknown-linux): matchGroupArity Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10426 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler