[Nix-dev] Re: WIKI question misc.collection, multiple ghc in PATH, "bit of problem",

[Marc Weber]

Excerpts from Peter Simons's message of Tue Aug 23 15:35:48 +0200 2011:
> yes, but that is not issue I'm concerned about. The problem I see is
> that this collision will not be detected.

There are two possible collisions:
1) misc.collection and any other package you've installed
2) packages within one misc.collection.

Neither is detected cause the additional packages to be installed are
considered lasts by env builder.

nixpkgs contains top level attr buildEnv which could be used instead.
This would fix 1) and 2). However in the case having different ghc's
you should eventually create one collection (based on buildEnv) for each
version. Then nix-env -iA should report collisions and let you choose
(untested).

Marc Weber