Please don't deprecate Haskell 98 modules.

Isaac Dupree ml at
Sun Mar 14 22:19:53 EDT 2010

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> 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:
> 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?


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