Move checkPredefError from GF.Compile.Compute.ConcreteLazy to GF.Grammar.Macros

Also simplified its type.

src/compiler/GF/Grammar/Macros.hs

@@ -225,6 +225,12 @@ isPredefConstant t = case t of
   Q (mod,_) | mod == cPredef || mod == cPredefAbs -> True
   _                                               -> False
 
+checkPredefError :: Monad m => Term -> m Term
+checkPredefError t =
+    case t of
+      Error s -> fail ("Error: "++s)
+      _ -> return t
+
 cnPredef :: Ident -> Term
 cnPredef f = Q (cPredef,f)