[commit: ghc] master: Extend `Foldable` class with `length` and `null` methods (e5cca4a)

[Joachim Breitner]

Hi,


Am Sonntag, den 28.09.2014, 13:07 +0000 schrieb git at git.haskell.org:
> commit e5cca4ab246ca2d1ecdd7c39eefd3157547cb6aa
> Author: Herbert Valerio Riedel <hvr at gnu.org>
> Date:   Sun Sep 28 13:02:53 2014 +0200
> 
>     Extend `Foldable` class with `length` and `null` methods
>     
>     This completes the `Foldable` class by two important operations which
>     this way can be optimised for the underlying structure more easily.
>     
>     A minor fix for the `containers` submodule was needed to due name clash
>     
>     Addresses #9621
>     
>     Reviewed By: ekmett, dfeuer, austin
>     
>     Differential Revision: https://phabricator.haskell.org/D250

this broke nofib:

==nofib== para: time to compile Main follows...
/data1/ghc-builder/logs/ghc-tmp-REV/inplace/bin/ghc-stage2 -O2 -Rghc-timing -H32m -hisuf hi -rtsopts -c Main.lhs -o Main.o

Main.lhs:517:32:
    No instance for (Foldable t0) arising from a use of ‘step’
    The type variable ‘t0’ is ambiguous
    Relevant bindings include
      par1' :: [t0 a] -> [[t0 a]] (bound at Main.lhs:516:2)
    Note: there are several potential instances:
      instance Foldable ((,) a) -- Defined in ‘Data.Foldable’
      instance GHC.Arr.Ix i => Foldable (GHC.Arr.Array i)
        -- Defined in ‘Data.Foldable’
      instance Foldable (Either a) -- Defined in ‘Data.Foldable’
      ...plus three others
    In the first argument of ‘fold1’, namely ‘step’
    In the second argument of ‘(.)’, namely ‘fold1 step start’
    In the second argument of ‘(.)’, namely
      ‘minWith cost . fold1 step start’
<<ghc: 93451064 bytes, 44 GCs, 4435640/8217616 avg/max bytes residency (4 samples), 31M in use, 0.001 INIT (0.001 elapsed), 0.051 MUT (0.056 elapsed), 0.057 GC (0.057 elapsed) :ghc>>


Greetings,
Joachim

-- 
Joachim “nomeata” Breitner
  mail at joachim-breitner.de • http://www.joachim-breitner.de/
  Jabber: nomeata at joachim-breitner.de  • GPG-Key: 0xF0FBF51F
  Debian Developer: nomeata at debian.org

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: This is a digitally signed message part
URL: <http://www.haskell.org/pipermail/ghc-devs/attachments/20140929/fe390d6e/attachment.sig>