X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FMatchLit.lhs;h=610a423b1d04d82649eedf712de696bdd4f0c6e3;hb=6202305819577fce2b11ab509ed94422775df30e;hp=2cdab30bf8b162c0059b9182b1eab6385bdfb7b7;hpb=90dc9026b091be5cca5da4c6cbd3713ecc493361;p=ghc-hetmet.git

diff --git a/compiler/deSugar/MatchLit.lhs b/compiler/deSugar/MatchLit.lhs
index 2cdab30..610a423 100644
--- a/compiler/deSugar/MatchLit.lhs
+++ b/compiler/deSugar/MatchLit.lhs
@@ -6,6 +6,13 @@
 Pattern-matching literal patterns
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module MatchLit ( dsLit, dsOverLit, hsLitKey, hsOverLitKey,
 		  tidyLitPat, tidyNPat, 
 		  matchLiterals, matchNPlusKPats, matchNPats ) where
@@ -27,12 +34,10 @@ import TcType
 import Type
 import PrelNames
 import TysWiredIn
-import PrelNames
 import Unique
 import Literal
 import SrcLoc
 import Ratio
-import SrcLoc
 import Outputable
 import Util
 import FastString
@@ -183,7 +188,8 @@ matchLiterals :: [Id]
 	      -> DsM MatchResult
 
 matchLiterals (var:vars) ty sub_groups
-  = do	{	-- Deal with each group
+  = ASSERT( all notNull sub_groups )
+    do	{	-- Deal with each group
 	; alts <- mapM match_group sub_groups
 
 	 	-- Combine results.  For everything except String