X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcErrors.lhs;h=c040473e65ee7157eb334008791479afcb47d636;hb=d93785d99261a433075dcbac8c388730a4dec64f;hp=873af7385c11354943dfd05376fa6e9f0140a9af;hpb=bac10a99aba7d223d70b93f398d5239a166e929f;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcErrors.lhs b/compiler/typecheck/TcErrors.lhs
index 873af73..c040473 100644
--- a/compiler/typecheck/TcErrors.lhs
+++ b/compiler/typecheck/TcErrors.lhs
@@ -343,11 +343,9 @@ getUserGivens (CEC {cec_encl = ctxt})
   where 
     givens = foldl (\gs ic -> ic_given ic ++ gs) [] ctxt
     user_givens | opt_PprStyle_Debug = givens
-                | otherwise          = filterOut isSelfDict givens
-       -- In user mode, don't show the "self-dict" given
-       -- which is only added to do co-inductive solving
-       -- Rather an awkward hack, but there we are
-       -- This is the only use of isSelfDict, so it's not in an inner loop
+                | otherwise          = filterOut isSilentEvVar givens
+       -- In user mode, don't show the "silent" givens, used for
+       -- the "self" dictionary and silent superclass arguments for dfuns
 \end{code}
 
 
@@ -595,10 +593,13 @@ reportDictErrs ctxt wanteds orig
                           <+> ptext (sLit "to the context of")
 	           , nest 2 $ pprErrCtxtLoc ctxt ]
 
-    	fixes2 | null instance_dicts = []
-	       | otherwise	     = [sep [ptext (sLit "add an instance declaration for"),
-				        pprTheta instance_dicts]]
-	instance_dicts = filterOut isTyVarClassPred wanteds
+        fixes2 = case instance_dicts of
+                   []  -> []
+                   [_] -> [sep [ptext (sLit "add an instance declaration for"),
+                                pprTheta instance_dicts]]
+                   _   -> [sep [ptext (sLit "add instance declarations for"),
+                                pprTheta instance_dicts]]
+        instance_dicts = filterOut isTyVarClassPred wanteds
 		-- Insts for which it is worth suggesting an adding an 
 		-- instance declaration.  Exclude tyvar dicts.