[commit: ghc] master: Remove Show instance for Forest (4ecfc7f)

[Simon Peyton Jones]

Repository : ssh://darcs.haskell.org//srv/darcs/ghc

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/4ecfc7ffab0b8578490f7fbe8aa8912f4af1a76a

>---------------------------------------------------------------

commit 4ecfc7ffab0b8578490f7fbe8aa8912f4af1a76a
Author: Simon Peyton Jones <simonpj at microsoft.com>
Date:   Wed Mar 28 07:02:23 2012 +0100

    Remove Show instance for Forest
    
    A Forest is just a list, and we have a Show instance for
    lists already.  We don't need a special Show instance for
    Forests.  If we change our minds we can add a newtype,
    but I don't think it's worth it.
    
    Fixes Trac #5960

>---------------------------------------------------------------

 compiler/utils/Digraph.lhs |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/compiler/utils/Digraph.lhs b/compiler/utils/Digraph.lhs
index 1bb4606..a2b4015 100644
--- a/compiler/utils/Digraph.lhs
+++ b/compiler/utils/Digraph.lhs
@@ -429,12 +429,6 @@ instance Show a => Show (Tree a) where
 showTree :: Show a => Tree a -> String
 showTree  = drawTree . mapTree show
 
-instance Show a => Show (Forest a) where
-  showsPrec _ f s = showForest f ++ s
-
-showForest :: Show a => Forest a -> String
-showForest  = unlines . map showTree
-
 drawTree        :: Tree String -> String
 drawTree         = unlines . draw