Proposal: deepseq should not depend on containers

Johan Tibell johan.tibell at
Wed Dec 29 18:36:10 CET 2010

On Wed, Dec 29, 2010 at 2:41 PM, Christian Maeder
<Christian.Maeder at> wrote:
> I don't think, that orphaned instances can be avoided in the long run.
> Therefore I would rather see a separate package for the NFData instances
> of container types.

Why not? The general recipe is to define type classes in separate
packages so they can appear on the bottom of the dependency pyramid.
That way any package that defines a data type can depend on the
package that defines the type class and thus avoid creating orphan

Orphan instances should be avoided as they can cause hard to prevent
and hard to fix breakages in large code bases.


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