A more useful Monoid instance for Data.Map

Ian Lynagh ian at well-typed.com
Tue Mar 12 18:18:40 CET 2013

On Tue, Mar 12, 2013 at 11:06:22AM -0400, Ben Gamari wrote:
>   2) We decide it is acceptable to break users code multiple times, drop
>      the Monoid instance and reintroduce the new instance after some
>      delay. The length of this delay could range from no delay at all
>      (allowing folks to quickly move to the new instance, although
>      potentially unwittingly) to several months (hoping that most users
>      will realize the change during this window).

If we're talking about containers, if you want a meaningful delay, you'd
probably need at least one GHC+HP major release with no instance, and
and then the new instance would come with the next GHC+HP major release.
i.e. the delay would be at least a year.


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