[commit: ghc] master: Shortcut a test in exprIsOk (d357f52)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/d357f526582e3c4cd4fbda5d73695fc81121b69a/ghc

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

commit d357f526582e3c4cd4fbda5d73695fc81121b69a
Author: David Feuer <david.feuer at gmail.com>
Date:   Tue Mar 14 16:43:37 2017 -0400

    Shortcut a test in exprIsOk
    
    `exprIsOk` didn't shortcut properly when checking `case` (it used
    `foldl` inappropriately). Fix that.
    
    Reviewers: austin, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D3343


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d357f526582e3c4cd4fbda5d73695fc81121b69a
 compiler/coreSyn/CoreUtils.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/compiler/coreSyn/CoreUtils.hs b/compiler/coreSyn/CoreUtils.hs
index dce7ef9..3dfb52f 100644
--- a/compiler/coreSyn/CoreUtils.hs
+++ b/compiler/coreSyn/CoreUtils.hs
@@ -1130,8 +1130,8 @@ exprIsOk ok_app e
     go _ (Type {})                    = True
     go _ (Coercion {})                = True
     go n (Cast e _)                   = go n e
-    go n (Case scrut _ _ alts)        = foldl (&&) (ok scrut)
-                                        [ go n rhs | (_,_,rhs) <- alts ]
+    go n (Case scrut _ _ alts)        = ok scrut &&
+                                        and [ go n rhs | (_,_,rhs) <- alts ]
     go n (Tick t e) | tickishCounts t = False
                     | otherwise       = go n e
     go n (Lam x e)  | isRuntimeVar x  = n==0 || go (n-1) e