ANNOUNCE: GHC 6.12.1 Release Candidate 1

Antoine Latter aslatter at
Wed Oct 14 18:51:13 EDT 2009

On Wed, Oct 14, 2009 at 4:34 AM, Simon Marlow <marlowsd at> wrote:
> template-haskell is a one of the packages that we call "wired-in", because
> GHC needs to generate references to some of the things that it defines.  To
> make GHC independent of the version of the template-haskell package, we
> internally strip off the version number when referring to template-haskell.
> Now, this doesn't completely explain the error you're seeing.  When it
> starts up, GHC has to decide which template-haskell package is the
> "wired-in" one, and my guess is that it picked the other one (because it is
> newer).  You could find out by running GHC with the -v flag.  I think GHC is
> assuming that when you have multiple versions of a wired-in package that the
> older ones are wrappers around the newer ones (like base-3 and base-4), but
> that assumption doesn't hold in your case.
> Installing a new version of a wired-in package is going to be problematic,
> but we ought to be able to at least improve the diagnostics.

Does it make sense to do releases of the template-haskell package on
to hackage? It's a bit misleading if I can't then do anything to the
package that doesn't leave me broken.

(I guess I can `cabal unpack` into my GHC source directory to get a
different version ...)


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