[ghc-steering-committee] #380 GHC2021: Voting starts

Eric Seidel eric at seidel.io
Fri Dec 4 12:16:48 UTC 2020


Ah yes, I meant to explain that I have a minor objection to the instances generated by EmptyDataDeriving. The Eq and Ord instances are defined for bottom inputs while Show is undefined, which is oddly inconsistent. If Eq and Ord forced their arguments I would have voted for including EmptyDataDeriving. 

Sent from my iPhone

> On Dec 4, 2020, at 04:36, Joachim Breitner <mail at joachim-breitner.de> wrote:
> 
> Hi Eric,
> 
> probably not very relevant (both extensions far above the quorum) but
> it seems odd to include
> 
>> EmptyDataDecls: yes
> 
> 
> but then say 
> 
>> EmptyDataDeriving: no
> 
> Als note that the docs at
> https://downloads.haskell.org/ghc/latest/docs/html/users_guide/glasgow_exts.html#extension-EmptyDataDeriving
> say “The EmptyDataDeriving flag is only required to enable deriving of
> these four “standard” type classes (which are mentioned in the Haskell
> Report). Other extensions to the deriving mechanism, which are
> explained below in greater detail, do not require EmptyDataDeriving to
> be used in conjunction with empty data types.”
> 
> So enabling the other DerivingFoo extensions without EmptyDataDeriving
> is somewhat non-uniform.
> 
> Cheers,
> Joachim
> -- 
> Joachim Breitner
>  mail at joachim-breitner.de
>  http://www.joachim-breitner.de/
> 
> 
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