#8961: Require PatternSynonyms language extension to *use* pattern synonyms -------------------------------------+------------------------------------- Reporter: cactus | Owner: cactus Type: bug | Status: closed Priority: normal | Milestone: 7.8.1 Component: Compiler (Type | Version: 7.8.1-rc2 checker) | Keywords: Resolution: fixed | Architecture: Unknown/Multiple Operating System: Unknown/Multiple | Difficulty: Easy (less than 1 Type of failure: None/Unknown | hour) Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by tibbe): I think it's very attractive to allow the change to be transparent to the user, as Isaac said. Imagine we want to change `String` to be an opaque type with a different representation. We could use a pattern synonym (and expression synonym?) to allow users who use `(:)` to be none the wiser. I admit that I haven't thought about all the implications though. Would it really be transparent to the user if a real constructor or a synonym is used? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8961#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler