#11555: catch _|_ breaks at -O1 -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 8.0.1-rc2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Very helpful! I know what is happening. Everything works fine until `CorePrep`. At that point we have {{{ catch# (lazy (f x)) blah }}} Now `CorePrep` * Replaces `lazy e` by `e` * Converts to ANF, using `let` or `case` depending on whether the function is strict Unfortunately, that results in {{{ case f x of r -> catch# r blah }}} which is wrong of course. We need that `lazy` to defeat the call-by-value transformation too. So our fix is right; this is really a bug in the implementation of `lazy`. I don't have a fix for this yet, but we have some progress. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11555#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler