diff --git a/Front.hs b/Front.hs
index 59c9a0a..38fa355 100644
--- a/Front.hs
+++ b/Front.hs
@@ -411,6 +411,7 @@ instance WeakDesugar HsDecl where
     wds (HsTypeSig loc ns ty)=HsTypeSig loc ns ty
     wds (HsDataDecl loc [] n vs cdecls [])=HsDataDecl loc [] n vs cdecls []
     wds (HsDataDecl _ _ _ _ _ _)=error "WeakDesugar: HsDataDecl: context/deriving is not supported"
+    wds (HsInfixDecl loc assoc lv ops)=HsInfixDecl loc assoc lv ops
 
 instance WeakDesugar HsExp where
     wds (HsApp e0 e1)=HsApp (wds e0) (wds e1)
diff --git a/auto-test b/auto-test
index 906355e..86b32a8 100755
--- a/auto-test
+++ b/auto-test
@@ -17,7 +17,7 @@ and test_bf test/LocalFun.hs
 and test_bf test/Lambda.hs
 and test_bf test/Arithmetic.hs
 and test_bf test/ShowList.hs
-# and test_bf test/QuickSort.hs
+and test_bf test/QuickSort.hs
 # and test_bf test/TypeClass.hs
 # and test_bf test/ConstPattern.hs
 # and test_bf test/
diff --git a/test/Prelude.hs b/test/Prelude.hs
index 724d478..5d170ec 100644
--- a/test/Prelude.hs
+++ b/test/Prelude.hs
@@ -1,5 +1,7 @@
 
+infixr 0 $
 f $ x=f x
+
 f $! x=x `seq` (f x)
 
 data Bool
@@ -99,8 +101,16 @@ filter f (x:xs)
     |n `eqByte` 0 = x
     |otherwise    = xs !! (n `subByte` 1)
 
+{- I don't know why, but this code doesn't work!
 []++ys=ys
 (x:xs)++ys=x:(xs++ys)
+-}
+
+xs ++ ys=
+    case xs of
+        []   -> ys
+        x:xs -> x:(xs++ys)
+    
 
 length []=0
 length (x:xs)=1 `addByte` (length xs)
diff --git a/test/QuickSort.hs b/test/QuickSort.hs
new file mode 100644
index 0000000..65721a6
--- /dev/null
+++ b/test/QuickSort.hs
@@ -0,0 +1,9 @@
+
+main=outputStr Halt (qsort "etsb")
+
+qsort []=[]
+qsort (x:xs)=qsort (filter (gtByte x) xs)++[x]++qsort (filter (leByte x) xs)
+
+outputStr k []=k
+outputStr k (x:xs)=Output x (outputStr k xs)
+
diff --git a/test/ShowList.hs b/test/ShowList.hs
index 7440f0d..9893e88 100644
--- a/test/ShowList.hs
+++ b/test/ShowList.hs
@@ -1,6 +1,6 @@
 
 
-main=outputStr Halt (map showByte1 [1,2,3,4])
+main=outputStr Halt ((map showByte1 [1,2,3])++"\n")
 
 showByte1 x=addByte '0' x