Names for general merge tactics in Data.Map

David Feuer david.feuer at
Thu Aug 18 20:55:48 UTC 2016

On Thu, Aug 18, 2016 at 4:46 PM, Henning Thielemann <
lemming at> wrote:
> In the past, it caused problems to install a new 'containers' on an old
> Is this problem solved?

I believe you should be able to install it in a sandbox without any
trouble. AFAIK, the issue is that the GHC API is fixed to whichever version
of containers came with GHC, so the types exposed by a new version of
containers will not match the ones in the ghc pseudo-package. As long as
you're not trying to use the GHC API with the new containers, I believe you
should be fine.

>> 1. It allows the user to produce invalid maps. Unlike other functions
>> that do so, it's not clear that it offers any significant efficiency
>> benefit (once generalMerge is added).
> How about adding WARNING or DEPRECATED?

DEPRECATED is only appropriate if it's going to be removed. WARNINGs can
only be suppressed with a -Wno-warnings-deprecations flag, which makes me a
bit reluctant to use them.
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