[GHC] #3709: Data.Either.partitionEithers is not lazy enough

[Nicolas Pouillard]

Excerpts from Duncan Coutts's message of Fri Dec 04 18:22:05 +0100 2009:
> On Fri, 2009-12-04 at 01:19 +0000, Malcolm Wallace wrote:
> > >>> No non-bottoming program
> > >>> has changed, but fewer programs fail now. I find it hard to imagine
> > >>> that anyone could have been relying on getting a crash here.
> > >>
> > >> Making something more lazy can cause a memory leak.
> 
> > To come back to the specifics of partitionEithers, is anyone arguing  
> > that, in this case, the original over-strictness is either  
> > intentional, or useful?
> 
> I don't think anyone is complaining about this specific case. I think we
> agree that the general principle is to make things lazy except where
> there are compelling reasons to do otherwise.

+1 (for a lazier partitionEithers, intersperse and intercalate)

-- 
Nicolas Pouillard
http://nicolaspouillard.fr