#9857: GHC 7.9 panics (simplifier ticks exhausted) on `half-0.2` -------------------------------------+------------------------------------- Reporter: hvr | Owner: simonpj Type: bug | Status: new Priority: high | Milestone: 7.10.1 Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: Compile- | Blocked By: time crash | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by simonpj): Fixed by this (whose commit message contains a mis-typed ticket number) {{{ commit fbb42b2ea42b6467135f26db47d9c296e7ad75a3 Author: Simon Peyton Jones <simonpj@microsoft.com> Date: Sat Dec 13 22:47:01 2014 +0000 Pattern-synonym matcher and builder Ids must be *LocalIds* This easy-to-make mistake meant that pattern-synonym matcher and builder Ids weren't being treated as locally defined by the simpplier. That meant that we never looked up them up in the environment, got an out-of-date unfolding, which made the Simplifier fall into an infinite loop. This was the cause of Trac #98587, but it was quite tricky to find! In a separate patch I'll make Lint check for locally-bound GlobalIds, since they are always an error. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9857#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler