#14777: panic when using a function defined in terms of `error` -------------------------------------+------------------------------------- Reporter: zilinc | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Resolution: | Keywords: Operating System: Linux | 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 tdammers): Managed to reproduce the panic on 8.2.1; GHC HEAD builds cleanly. Defining the following function in `Surface.hs`, and using that instead of any calls to `__impossible` in `Desugar.hs`, also allows me to build cleanly on 8.2.1: {{{ __impossibleDef :: a __impossibleDef = error "impossible" }}} The unmodified example also builds cleanly without optimizations. Which suggests that some optimization pass produces a situation that hits a bug somewhere, and that the difference between `__impossible` and `__impossibleDef` is enough to trigger or not trigger it. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14777#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler