#9913: Discrepancy in type synonym definition and usage -------------------------------------+------------------------------------- Reporter: | Owner: Iceland_jack | Status: closed Type: bug | Milestone: Priority: lowest | Version: 7.8.3 Component: Compiler | Keywords: (Parser) | Architecture: x86 Resolution: invalid | Difficulty: Unknown Operating System: | Blocked By: Unknown/Multiple | Related Tickets: Type of failure: GHC | rejects valid program | Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by nomeata): * status: new => closed * resolution: => invalid Comment: Thanks for your report. I don’t think this is a bug. There is a conceptual difference between the declaration, where the argument to the type synonyms are declared (and hence have to be variables), and the use of a type synonym, where parameters are type expressions. Note that you can use `Alg Maybe`, but cannot define `type Alg Maybe a = Maybe a -> a`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9913#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler