The PVP ought to mention dependency bounds (Was: Growing Haskell Platform)

Johan Tibell johan.tibell at
Mon Dec 10 17:02:44 CET 2012

On Sat, Dec 8, 2012 at 12:11 PM, Duncan Coutts
<duncan.coutts at> wrote:
> But yes it is true that the "real" API of a package is in the version
> number of the package itself, and the versions of all the packages
> which are "exposed" by that package (meaning packages that define
> types that are mentioned in the api of the exposing package). But it
> that has the property that I only notice changes in the types in those
> dependencies if I also depend on them directly myself. So we can get
> away with specifying local info, and not have to encode the full
> transative info (I think).

It's worse than that. The failure to build in my example above is a
failure to find a valid install plan due to conflicting dependency
ranges, not due to clashing symbols from different package versions.
It happens even with private dependencies!

-- Johan

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