incorrect dependencies on template-haskell

Ivan Lazar Miljenovic ivan.miljenovic at
Tue Oct 4 00:36:25 CEST 2011

On 4 October 2011 05:47, Brandon Moore <brandon_m_moore at> wrote:
>> From: Antoine Latter <aslatter at>
>> Sent: Sunday, October 2, 2011 9:21 PM
>> On Sun, Oct 2, 2011 at 8:31 PM, Brandon Moore <brandon_m_moore at>
>> wrote:
> ...
>>>  If the package isn't meant to be upgraded, should it be on
>>>  hackage at all?
>> Using an install of the template-haskell library other than the one
>> GHC was built against will make GHC unhappy - the operations in the
>> library won't type-check against the built-in GHC magic.

I see two possible reasons for having it (along with other boot
libraries) still on Hackage:

1) An archive of previous versions

2) In case some other compiler one day supports TH.

> If so, the package should not be on hackage with dependencies that lead
> cabal-install to try to upgrade it. I see three ways to fix this
> [snip]
>   3) Fix cabal-install to avoid the package.

If ghc-pkg has a notion of "this is a boot library, don't upgrade me!"
I think this is a viable option; it may also make it easier for distro
packagers to be able to determine deps.

Ivan Lazar Miljenovic
Ivan.Miljenovic at

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