Semigroup instance #25

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1. spl

   added

   enhancement

   on Feb 10, 2016
2. spl

   self-assigned this

   on Feb 10, 2016
3. spl commented on Feb 10, 2016

   

   spl

   on Feb 10, 2016

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   @gregwebs Since Semigroup is in base for GHC 8.0, I think it makes sense to have an instance for it in dlist. What would you like to do about dlist-instances? Would it make sense to put an upperbound on the base dependency for dlist-instances so that the two packages do not conflict? Alternatively, you don't have to do anything. I think users of dlist will need to add CPP anyways if they want to support dlist with dlist-instances and dlist with the Semigroup instance.
4. gregwebs commented on Feb 12, 2016

   

   gregwebs

   on Feb 12, 2016

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   Seems like dlist-instances should include CPP To exclude the instance for GHC 8. That will make it possible for some users not to change anything
5. spl commented on Feb 15, 2016

   

   spl

   on Feb 15, 2016

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   Good idea. I'll put in the change sometime in the next few weeks.
6. hvr commented on Feb 29, 2016

   

   hvr

   on Feb 29, 2016

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   Btw, there's also the option (assuming @ekmett is ok with it) to have the semigroups package provide non-orphan DList instances for GHC<8 (semigroups already does this for a few other packages whose authors prefered to not add a dependency on semigroups)
7. ekmett commented on Feb 29, 2016

   

   ekmett

   on Feb 29, 2016

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   I'm open to it. Toss me a patch.
8. spl

   added 7 commits that reference this issue on Jul 12, 2016

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit 603f228 is merged into the 'main' branch.

   603f228

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit 8e0481d is merged into the 'main' branch.

   8e0481d

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit cc487d4 is merged into the 'main' branch.

   cc487d4

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit 3e7a9d6 is merged into the 'main' branch.

   3e7a9d6

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit 8e547d1 is merged into the 'main' branch.

   8e547d1

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit 0f17548 is merged into the 'main' branch.

   0f17548

   Add Semigroup instance for GHC >= 8 (base >= 4.9)

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   This issue will close once commit f031b66 is merged into the 'main' branch.

   f031b66
9. spl commented on Jul 12, 2016

   

   spl

   on Jul 12, 2016

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   Finally got around to dealing with this.

   @gregwebs See #27 (in particular f031b66) for how I'm doing the Semigroup instance. This is going into dlist-0.8. I suppose it would make sense to use CPP with !MIN_VERSION_dlist(0,8,0) wrapping the instance.

   @ekmett Since there is already dlist-instances with an orphan instance of Semigroup for DList and people are using it, I think it can remain as the source for that instance.
10. spl

    closed this as completedin f031b66on Jul 17, 2016
11. hvr

    added a commit that references this issue on Jul 19, 2016

    Make dlist-instances compatible with dlist-0.8+

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    f844611
12. ekmett commented on Jun 20, 2017

    

    ekmett

    on Jun 20, 2017

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    @spl Given that the problem will clear up over a couple of ghc releases and fade into obscurity I can blissfully ignore the orphan issue. shrug