Nonlinear patterns in concrete syntax are now detected and reported as errors

Before, they were silently converted to linear patterns.
Nonlinear patterns in MorphoCat.gf, ParadigmsGre.gf and ParadigmsFin.gf have
been make linear by renaming pattern variables.

src/compiler/GF/Compile/Rename.hs

@@ -39,7 +39,7 @@ import GF.Grammar.Printer
 import GF.Data.Operations
 
 import Control.Monad
-import Data.List (nub)
+import Data.List (nub,(\\))
 import Text.PrettyPrint
 
 -- | this gives top-level access to renaming term input in the cc command
@@ -235,8 +235,14 @@ renameTerm env vars = ren vars where
 
 -- | vars not needed in env, since patterns always overshadow old vars
 renamePattern :: Status -> Patt -> Check (Patt,[Ident])
-renamePattern env patt = case patt of
-
+renamePattern env patt =
+    do r@(p',vs) <- renp patt
+       let dupl = vs \\ nub vs
+       unless (null dupl) $ checkError (hang (text "[C.4.13] Pattern is not linear:") 4
+                                             (ppPatt Unqualified 0 patt))
+       return r
+  where
+    renp patt = case patt of
       PMacro c -> do
         c' <- renid $ Vr c
         case c' of
@@ -301,8 +307,6 @@ renamePattern env patt = case patt of
 
       _ -> return (patt,[])
 
- where 
-   renp  = renamePattern env
     renid = renameIdentTerm env
     renid' = renameIdentTerm' env