#13349: Make GHC handle orphan COMPLETE sets of conlikes better -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Like orphan rewrite rules, it's possible to define orphan `COMPLETE` sets. For instance: {{{#!hs module Foo where {-# COMPLETE False #-} }}} I suppose that we could define an orphan `COMPLETE` set as one that lives in a module where none of the conlikes are defined (or should we say "where one or more of the conlikes are not defined"? I'm not sure.) Like orphan `RULES`, orphan `COMPLETE` sets are important to track properly when transitively reading from interface files, as failing to bring an orphan `COMPLETE` set into scope could affect pattern-match exhaustivness warnings that users see. After discussing this with rwbarton and mpickering IRC, we decided that one of the two should happen: 1. Treat orphan `COMPLETE` sets like orphan `RULES`. That is, mark a module as an orphan if it defines an orphan `COMPLETE` set, and thread a "`COMPLETE` pragma visibility" state through various places. 2. Disallow orphan `COMPLETE` sets entirely. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13349 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler