#13381: "opt_univ fell into a hole" panic from rewrite rule -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): To make things even more interesting, this error does not occur on GHC 7.8 or 7.10. Here's the error you get with 7.10.3: {{{ GHCi, version 7.10.3: http://www.haskell.org/ghc/ :? for help [1 of 1] Compiling Crash ( Bug.hs, interpreted ) Bug.hs:25:23: Couldn't match type ‘Exp Int’ with ‘Int’ Expected type: Exp Int -> Iter (Exp Int) (Exp Char) Actual type: Int -> Iter (Exp Int) (Exp Char) In the first argument of ‘iterLoop’, namely ‘f’ In the first argument of ‘fromExp’, namely ‘(iterLoop f init)’ Bug.hs:25:25: Couldn't match expected type ‘Exp Int’ with actual type ‘Int’ In the second argument of ‘iterLoop’, namely ‘init’ In the first argument of ‘fromExp’, namely ‘(iterLoop f init)’ }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13381#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler