Re: PVP proposal: no upper bounds on non-upgradeable packages

Yeah. I think the real solution lies with cabal better knowing what libs ghc was baked/built with vs which can safely usually have a conflicting version in the user package db. This would be a nice use case for cabal / ghc-pkg better understanding private vs public dependencies too! (Eg user ByteString vs ghc ByteString ) This is starting to sound like a bunch of good ideas to try on cabal! :-) On Wednesday, April 9, 2014, Johan Tibell wrote:

On Wed, Apr 9, 2014 at 10:08 PM, Erik Hesselink javascript:_e(%7B%7D,'cvml','hesselink@gmail.com');

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The only constraint that actually makes sense for template-haskell is 'installed', which I have in my cabal.config. I think this should perhaps be built into cabal. This can then be combined with a constraint on the known versions of TH a package works with.

Adding "installed" to the user supplied constraints for base, template-haskell, and ghc-prim sounds sensible.