Elaborate for-all message slightly

diff --git a/compiler/rename/RnEnv.lhs b/compiler/rename/RnEnv.lhs
index a4c4afd..6c3567a 100644 (file)
--- a/compiler/rename/RnEnv.lhs
+++ b/compiler/rename/RnEnv.lhs
@@ -987,7 +987,8 @@ unknownNameErr rdr_name
         , extra ]
   where
     extra | rdr_name == forall_tv_RDR 
-         = ptext (sLit "Perhaps you intended to use -XRankNTypes or similar flag")
+         = vcat [ptext (sLit "Perhaps you intended to use -XRankNTypes or similar flag"),
+                 ptext (sLit "to enable explicit-forall syntax: forall <tvs>. <type>?")]
          | otherwise = empty
 
 unknownSubordinateErr :: SDoc -> RdrName -> SDoc