#14112: bang patterns on pattern synonyms? (left vs right hand sides) -------------------------------------+------------------------------------- Reporter: carter | Owner: RyanGlScott Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: | PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by RyanGlScott): * owner: (none) => RyanGlScott * milestone: => 8.4.1 Comment: The only reason I don't favor (B) is because it's not always clear how you'd translate bang patterns on the RHS of an implicitly bidirectional pattern synonym to bang patterns for the builder arguments. For example, how would this be desugared? {{{#!hs pattern Foo a = Just !(Just a) }}} The only sensible thing I could envision here would be to silently ignore the bang pattern, but that makes me just as uncomfortable as it does you. I'd be willing to implement option (A). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14112#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler