diff --git a/src/GF/Compile/CheckGrammar.hs b/src/GF/Compile/CheckGrammar.hs
index 037d07072..3b3e9eaa6 100644
--- a/src/GF/Compile/CheckGrammar.hs
+++ b/src/GF/Compile/CheckGrammar.hs
@@ -664,7 +664,7 @@ checkLType env trm typ0 = do
 pattContext :: LTEnv -> Type -> Patt -> Check Context
 pattContext env typ p = case p of
   PV x -> return [(x,typ)]
-  PP q c ps | q /= cPredef -> do
+  PP q c ps | q /= cPredef || prt c == "CC" -> do ---- why this /=? AR 6/1/2006
     t <- checkErr $ lookupResType cnc q c
     (cont,v) <- checkErr $ typeFormCnc t
     checkCond ("wrong number of arguments for constructor in" +++ prt p) 
diff --git a/src/GF/Compile/Rename.hs b/src/GF/Compile/Rename.hs
index 70451a25a..c3369e9ef 100644
--- a/src/GF/Compile/Rename.hs
+++ b/src/GF/Compile/Rename.hs
@@ -221,14 +221,15 @@ renamePattern env patt = case patt of
 
   PC c ps -> do
     c' <- renameIdentTerm env $ Cn c
-    psvss <- mapM renp ps
-    let (ps',vs) = unzip psvss
     case c' of
-      QC p d -> return (PP p d ps', concat vs)
-      Q  p d -> return (PP p d ps', concat vs) ---- should not happen
+      QC p d -> renp $ PP p d ps
+      Q  p d -> renp $ PP p d ps
       _ -> prtBad "unresolved pattern" c' ---- (PC c ps', concat vs)
 
-----  PP p c ps -> (PP p c ps',concat vs') where (ps',vs') = unzip $ map renp ps
+  PP p c ps -> do
+    psvss <- mapM renp ps
+    let (ps',vs) = unzip psvss
+    return (PP p c ps', concat vs)
 
   PV x -> case renid patt of
     Ok p -> return (p,[])
diff --git a/src/GF/Grammar/AppPredefined.hs b/src/GF/Grammar/AppPredefined.hs
index c8710f32d..442328eb4 100644
--- a/src/GF/Grammar/AppPredefined.hs
+++ b/src/GF/Grammar/AppPredefined.hs
@@ -35,6 +35,7 @@ typPredefined c@(IC f) = case f of
   "PBool"  -> return typePType
   "PFalse" -> return $ cnPredef "PBool"
   "PTrue"  -> return $ cnPredef "PBool"
+  "CC"     -> return $ mkFunType [typeTok,typeTok] typeTok
   "dp"     -> return $ mkFunType [cnPredef "Int",typeTok] typeTok
   "drop"   -> return $ mkFunType [cnPredef "Int",typeTok] typeTok
   "eqInt"  -> return $ mkFunType [cnPredef "Int",cnPredef "Int"] (cnPredef "PBool")
@@ -73,6 +74,7 @@ appPredefined t = case t of
     App (Q (IC "Predef") (IC f)) z0 -> do
      (z,_) <- appPredefined z0
      case (f, norm z, norm x) of
+      ("CC",   K r,    K s) -> retb $ K (r ++ s)
       ("drop", EInt i, K s) -> retb $ K (drop (fi i) s)
       ("take", EInt i, K s) -> retb $ K (take (fi i) s)
       ("tk",   EInt i, K s) -> retb $ K (take (max 0 (length s - fi i)) s)
diff --git a/src/GF/Grammar/PatternMatch.hs b/src/GF/Grammar/PatternMatch.hs
index db6f7dc5b..b996efa0a 100644
--- a/src/GF/Grammar/PatternMatch.hs
+++ b/src/GF/Grammar/PatternMatch.hs
@@ -66,6 +66,12 @@ tryMatch (p,t) = do
             p `eqStrIdent` f && length pp == length tt ->
          do matches <- mapM tryMatch (zip pp tt)
             return (concat matches)
+
+      (PP (IC "Predef") (IC "CC") [p1,p2], ([],K s, [])) -> do
+         let cuts = [splitAt n s | n <- [0 .. length s]] 
+         matches <- checks [mapM tryMatch [(p1,K s1),(p2,K s2)] | (s1,s2) <- cuts]
+         return (concat matches)
+
       (PP q p pp, ([], QC r f, tt)) | 
             -- q `eqStrIdent` r &&  --- not for inherited AR 10/10/2005
             p `eqStrIdent` f && length pp == length tt ->
@@ -97,6 +103,7 @@ isInConstantForm trm = case trm of
     App c a  -> isInConstantForm c && isInConstantForm a
     R r      -> all (isInConstantForm . snd . snd) r
     K _      -> True
+    Empty    -> True
     Alias _ _ t -> isInConstantForm t
     EInt _   -> True
     _       -> False ---- isInArgVarForm trm
diff --git a/src/GF/Source/SourceToGrammar.hs b/src/GF/Source/SourceToGrammar.hs
index cfd8ae827..97f8fbc75 100644
--- a/src/GF/Source/SourceToGrammar.hs
+++ b/src/GF/Source/SourceToGrammar.hs
@@ -521,6 +521,8 @@ transPatts :: Patt -> Err [G.Patt]
 transPatts p = case p of
   PDisj p1 p2 -> liftM2 (++) (transPatts p1) (transPatts p2)
   PC id patts -> liftM (map (G.PC id) . combinations) $ mapM transPatts patts
+  PQC q id patts -> liftM (map (G.PP q id) . combinations) (mapM transPatts patts)
+
   PR pattasss -> do
     let (lss,ps) = unzip [(ls,p) | PA ls p <- pattasss]
         ls = map LIdent $ concat lss