Re: [GHC] #11276: GHC hangs/takes an exponential amount of time with simple program

#11276: GHC hangs/takes an exponential amount of time with simple program -------------------------------------+------------------------------------- Reporter: mpickering | Owner: gkaracha Type: bug | Status: new Priority: highest | Milestone: 8.0.1 Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Ben Gamari ): In [changeset:"0acdcf2482d24903b504e6b34fa745ef855ff00d/ghc" 0acdcf24/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="0acdcf2482d24903b504e6b34fa745ef855ff00d" Avoid generating guards for CoPats if possible (Addresses #11276) When translating a `CoPat` to `PmPat` check whether the wrapper is just a hole or a cast with refl. In these cases we can safely drop the wrapper and generate less guard patterns. Fixes T11276. Test Plan: validate Reviewers: bgamari, austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D1729 GHC Trac Issues: #11276 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11276#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler