[commit: packages/containers] cleaned_bugfix394, master, merge-doc-target, revert-408-bugfix_394: Kill getSingleton (dbed0dd)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/containers

On branches: cleaned_bugfix394,master,merge-doc-target,revert-408-bugfix_394
Link       : http://git.haskell.org/packages/containers.git/commitdiff/dbed0dd3e41cfcf3a38e9ea111a49f0ae8cddc76

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

commit dbed0dd3e41cfcf3a38e9ea111a49f0ae8cddc76
Author: David Feuer <David.Feuer at gmail.com>
Date:   Thu Dec 29 21:20:09 2016 -0500

    Kill getSingleton
    
    It's partial, and was used in a silly way for no particularly
    good reason. We still need a partial function, but we can write
    it where we use it.


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

dbed0dd3e41cfcf3a38e9ea111a49f0ae8cddc76
 Data/Sequence/Internal.hs | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/Data/Sequence/Internal.hs b/Data/Sequence/Internal.hs
index d2bfa04..5ec5a07 100644
--- a/Data/Sequence/Internal.hs
+++ b/Data/Sequence/Internal.hs
@@ -4072,10 +4072,6 @@ splitMapNode splt f s (Node3 ns a b c) = Node3 ns (f first a) (f second b) (f th
     (second, third) = splt (size b) r
 #endif
 
-getSingleton :: Seq a -> a
-getSingleton (Seq (Single (Elem a))) = a
-getSingleton _ = error "getSingleton: Not a singleton."
-
 ------------------------------------------------------------------------
 -- Zipping
 ------------------------------------------------------------------------
@@ -4099,7 +4095,10 @@ zipWith f s1 s2 = zipWith' f s1' s2'
 
 -- | A version of zipWith that assumes the sequences have the same length.
 zipWith' :: (a -> b -> c) -> Seq a -> Seq b -> Seq c
-zipWith' f s1 s2 = splitMap uncheckedSplitAt (\s a -> f a (getSingleton s)) s2 s1
+zipWith' f s1 s2 = splitMap uncheckedSplitAt goLeaf s2 s1
+  where
+    goLeaf (Seq (Single (Elem b))) a = f a b
+    goLeaf _ _ = error "Data.Sequence.zipWith'.goLeaf internal error: not a singleton"
 
 -- | /O(min(n1,n2,n3))/.  'zip3' takes three sequences and returns a
 -- sequence of triples, analogous to 'zip'.