Propsal: NoDatatypeContexts

[Neil Brown]

On 18/07/10 22:59, Ian Lynagh wrote:
> Hi all,
>
> H98 and H2010 allow a context to be given for datatypes, e.g. the
> "Eq a" in
>
>      data Eq a =>  Foo a = Constr a
>
> I have made a proposal to remove support for that context (ticket #139).
> More details are on the proposal wiki page:
>
>      http://hackage.haskell.org/trac/haskell-prime/wiki/NoDatatypeContexts
>
>
>    
To provide a data point: I was surprised to see CHP on the list of 
packages that didn't compile without data-type contexts, as I didn't 
realise I was using them.  I found one in a source file I haven't 
touched for a while, and removing it made no difference -- the library 
compiled fine.

I'm all for the proposal -- it stops people (like me!) inadvisedly using 
datatype contexts despite them not actually doing anything.

Thanks,

Neil.