#9721: RecordWildCards panic -------------------------------------+------------------------------------- Reporter: jorgemendes | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Keywords: | Operating System: Linux Architecture: x86 | Type of failure: Compile- Difficulty: Unknown | time crash Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- GHC 7.4.1 (Debian 7.7 and Ubuntu 12.04.5 LTS) panics with: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.4.1 for i386-unknown-linux): compiler/rename/RnPat.lhs:535:39-79: Irrefutable pattern failed for pattern gres@(gre : _) }}} I found a minimal test case to exemplify this issue: {{{#!hs module Foo where import Bar (Bar (Bar)) foo :: Bar -> () foo Bar {..} = () }}} {{{#!hs module Bar where data Bar = Bar { barA :: Int, barB :: Int } }}} A workaround is to import all data fields in module Foo: {{{#!hs import Bar (Bar (..)) }}} I also tried this with GHC 7.6.3 (Mac OS X), with no warnings nor errors. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9721 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler