#14685: Pragma to reset language extensions in module header -------------------------------------+------------------------------------- Reporter: mgsloan | Owner: (none) Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 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 mgsloan): I have considered it a it a bit, and my proposal does indeed imply a bit of a fiddly difference in build semantics depending on version. It turns out that I'd usually want that difference, because my primary use-case is protecting code from variation in extensions used by the build. However, if the protection is not possible, I still want it to try to build. I guess this ugly incantation could be used. {{{ {-# LANGUAGE CPP #-} #if __GLASGOW_HASKELL__ >= 804 {-# OPTIONS_GHC -X #-} #endif }}} So, if one cares about behavior consistency `LANGUAGE_RESET` should only be used as a protection from varying build configurations, *not* as a way to turn off all the default options from your package configuration. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14685#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler