#4347: Bug in unification of polymorphic and not-yet-polymorphic type -------------------------------------+------------------------------------- Reporter: dolio | Owner: Type: bug | Status: closed Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.1 (Type checker) | Keywords: Resolution: wontfix | Architecture: x86_64 (amd64) Operating System: Linux | Difficulty: Unknown Type of failure: GHC | Blocked By: rejects valid program | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => closed * resolution: => wontfix Comment: Dolio is right here. I've backed off from making ANY claims about what GHC does or does not do for impredicative polymorphism. Really the language extension flag should be deprecated because it is not supported either by proper theory about what inference should do, or by an implementation of that theory. Whatever happens right now happens by luck. I'm sure there is a route to a better story for impredicativity; but it is complex territory and there has been much else to do. So yes I'll close this ticket Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/4347#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler