diff --git a/src/compiler/GF/Compile/Compute/ConcreteNew.hs b/src/compiler/GF/Compile/Compute/ConcreteNew.hs
index a9ae63960..0edf43c8d 100644
--- a/src/compiler/GF/Compile/Compute/ConcreteNew.hs
+++ b/src/compiler/GF/Compile/Compute/ConcreteNew.hs
@@ -546,7 +546,7 @@ value2term' stop loc xs v0 =
 linPattVars p =
     if null dups
     then return pvs
-    else fail.render $ hang "Pattern is not linear:" 4 (ppPatt Unqualified 0 p)
+    else fail.render $ hang "Pattern is not linear. All variable names on the left-hand side must be distinct." 4 (ppPatt Unqualified 0 p)
   where
     allpvs = allPattVars p
     pvs = nub allpvs
diff --git a/src/compiler/GF/Compile/Rename.hs b/src/compiler/GF/Compile/Rename.hs
index 5eb83cd4b..aacf24c5b 100644
--- a/src/compiler/GF/Compile/Rename.hs
+++ b/src/compiler/GF/Compile/Rename.hs
@@ -236,7 +236,7 @@ renamePattern :: Status -> Patt -> Check (Patt,[Ident])
 renamePattern env patt =
     do r@(p',vs) <- renp patt
        let dupl = vs \\ nub vs
-       unless (null dupl) $ checkError (hang ("[C.4.13] Pattern is not linear:") 4
+       unless (null dupl) $ checkError (hang ("[C.4.13] Pattern is not linear. All variable names on the left-hand side must be distinct.") 4
                                              patt)
        return r
   where