#12025: Order of constraints forced (in pattern synonyms, type classes in comments) -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.1 checker) | Keywords: Resolution: | TypeApplications PatternSynonyms Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: 11513, 10928 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by Iceland_jack): Thanks for your responses. Replying to [comment:5 simonpj]:
We could do the same for pattern synonyms, so that {{{ pattern X' :: () => forall xxx. A [xxx] }}} means precisely {{{ pattern X' :: forall t. () => forall xxx. (t ~ [xxx]) => A t }}}
That sounds like a step in the right direction Simon but would this make the current meaning of {{{#!hs pattern X' :: () => forall xxx. A [xxx] }}} inexpressible (a pattern that only matches `A [xxx]`)? I want to be aware of the trade-offs, I don't have use for it personally -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12025#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler