Please don't deprecate Haskell 98 modules.

[Gwern Branwen]

On Sun, Mar 14, 2010 at 10:19 PM, Isaac Dupree
<ml at isaac.cedarswampstudios.org> wrote:
> On 03/14/10 22:11, Brandon S. Allbery KF8NH wrote:
>>
>> On Mar 14, 2010, at 17:55 , Gwern Branwen wrote:
>>>
>>> On Sat, Mar 13, 2010 at 11:06 AM, Ian Lynagh <igloo at earth.li> wrote:
>>>>
>>>> On Fri, Mar 12, 2010 at 08:44:46PM -0500, Gwern Branwen wrote:
>>>>>
>>>>> multiple patches which consisted solely of one line removing haskell98
>>>>> from the .cabal because the haskell98 modules *were not imported*.
>>>>
>>>> A general "Nothing from dependency is imported" warning would be great,
>>>> but trickier to implement. It's a similar problem to implementing
>>>> an "extension isn't used" warning.
>>>
>>> I've opened a ticket for this:
>>> http://hackage.haskell.org/trac/hackage/ticket/643
>>
>>
>> Actually, doesn't the instances-are-global thing make this essentially
>> impossible without whole-program analysis?
>
> GHC will not find an instance that's never imported, I believe. Therefore
> dependencies that are nowhere imported can always be safely removed.  Is
> this right?
>
> -Isaac

I would be rather surprised if it were not true!

-- 
gwern