[Typeable2] Re: ANNOUNCE: GHC 7.8.1 Release Candidate 1

[Simon Peyton Jones]

I think you need to import Data.OldTypeable to get Typeable2 and friends.  Pedro may remember more of the reasoning about backward compatibility.

| -----Original Message-----
| From: Christian Maeder [mailto:Christian.Maeder at dfki.de]
| Sent: 20 February 2014 16:09
| To: Simon Peyton Jones; Daniil Frumin
| Cc: glasgow-haskell-users at haskell.org
| Subject: Re: [Typeable2] Re: ANNOUNCE: GHC 7.8.1 Release Candidate 1
| 
| With "TypeableN " I mean, Typeable1, Typeable2, etc.
| Typeable2 was not supported (below) by ghc-7.8-rc1.
| 
| Where is the "backward compat"?
| 
| In fact, Typeable and Typeable2 mean the same thing for ghc-7.8-rc1 and
| ghc-7.6 resp.!
| 
| C.
| 
| Am 20.02.2014 17:00, schrieb Simon Peyton Jones:
| > | Can you not simply let ghc-7.8 interpret TypeableN as Typeable?
| >
| > Not really: ghc-7.8 does still support TypeableN I think (for backward
| compat reasons).  So it can't take it to mean two different things.
| >
| > | -----Original Message-----
| > | From: Glasgow-haskell-users [mailto:glasgow-haskell-users-
| > | bounces at haskell.org] On Behalf Of Christian Maeder
| > | Sent: 20 February 2014 15:51
| > | To: Daniil Frumin
| > | Cc: glasgow-haskell-users at haskell.org
| > | Subject: Re: [Typeable2] Re: ANNOUNCE: GHC 7.8.1 Release Candidate 1
| > |
| > | Yes, changing Typeable2 to Typeable in:
| > |
| > | {-# LANGUAGE StandaloneDeriving, DeriveDataTypeable #-} ...
| > | deriving instance Typeable Gr
| > |
| > | goes through with ghc-7.8-rc1.
| > |
| > | However, this change refuses to compile with ghc-7.6.3:
| > |
| > |      Expecting two more arguments to `Gr'
| > |      In the stand-alone deriving instance for `Typeable Gr'
| > |
| > | This is unfortunate, because I need to add conditional compilation
| > | to make my code compilable for the two most recent major versions of
| GHC.
| > |
| > | Can you not simply let ghc-7.8 interpret TypeableN as Typeable?
| > |
| > | Cheers Christian
| > |
| > | Am 13.02.2014 15:36, schrieb Daniil Frumin:
| > | > I think that the preferred solution is to get rid of the custom
| > | > Typeable(2) instances and just derive Typeable
| > | >
| > | > On Thu, Feb 13, 2014 at 5:22 PM, Christian Maeder
| > | > <Christian.Maeder at dfki.de> wrote:
| > | >> Hi,
| > | >>
| > | >> with ghc-7.8.20140130 I get the compilation error:
| > | >>
| > | >>      Not in scope: type constructor or class 'Typeable2'
| > | >>      Perhaps you meant 'Typeable' (imported from Data.Typeable)
| > | >>
| > | >> What is the recommend way to adjust my code or my dependencies?
| > | >>
| > | >> Cheers Christian
| > | >>
| > | >> Am 03.02.2014 23:35, schrieb Austin Seipp:
| > | >>>
| > | >>> We are pleased to announce the first release candidate for GHC
| > | 7.8.1:
| > | >>>
| > | >>>       http://www.haskell.org/ghc/dist/7.8.1-rc1/
| > | >>>       http://www.haskell.org/ghc/docs/7.8.1-rc1/html/
| > | >>>
| > | >>> This includes the source tarball and bindists for Windows,
| > | >>> Linux, OS X, FreeBSD, and Solaris, on x86 and x86_64. There is a
| > | >>> signed copy of the SHA256 hashes available (attached) using my
| > | >>> GPG key (keyid 0x3B58D86F).
| > | >>>
| > | >>> We plan to make the 7.8.1 RC2 release quite soon, as we're aware
| > | >>> of some existing issues.
| > | >>>
| > | >>> Please test as much as possible; bugs are much cheaper if we
| > | >>> find them before the release!
| > | >>>
| > | >>>
| > | >>>
| > | >>>
| > | >>> _______________________________________________
| > | >>> Glasgow-haskell-users mailing list
| > | >>> Glasgow-haskell-users at haskell.org
| > | >>> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
| > | >>>
| > | >>
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| > | >
| > | >
| > | >
| > |
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