#11352: Allow applying type to label -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 7.11 checker) | Resolution: | Keywords: ORF Operating System: Unknown/Multiple | Architecture: Type of failure: GHC rejects | Unknown/Multiple valid program | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by adamgundry): * owner: adamgundry => Comment: Hmm, this isn't as straightforward as I thought. We could change the type of `fromLabel` to be `forall x a . IsLabel x a => a`, and then implement `#answer` by replacing it with `fromLabel @"answer"`. That gives you the behaviour you want, but it means that error messages mention applications of `fromLabel`, e.g. {{{ Could not deduce (IsLabel "y" t) arising from the overloaded label ‘#y’ }}} becomes {{{ Could not deduce (IsLabel "y" t) arising from a use of ‘fromLabel’ }}} which is somewhat undesirable. Moreover, overloaded string/numeric literals are similarly incompatible with visible type application. So I'm inclined to leave things as they are: after all, you can always write `#answer :: Int`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11352#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler