From 7e3ec3f3aa3ecaf39cb4519f562ee20debcb5ece Mon Sep 17 00:00:00 2001
From: "simonpj@microsoft.com" <unknown>
Date: Fri, 8 Oct 2010 11:13:18 +0000
Subject: [PATCH] Suppress ambiguity errors if any other errors occur

---
 compiler/typecheck/TcErrors.lhs |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/compiler/typecheck/TcErrors.lhs b/compiler/typecheck/TcErrors.lhs
index 0ade93c..1254dd6 100644
--- a/compiler/typecheck/TcErrors.lhs
+++ b/compiler/typecheck/TcErrors.lhs
@@ -125,10 +125,9 @@ reportTidyWanteds ctxt unsolved
        ; when (null tv_eqs) $ groupErrs (reportFlat ctxt) others
        ; when (null tv_eqs) $ mapBagM_ (reportTidyImplic ctxt) implics
 
-       	   -- Only report ambiguity if no other errors happened
-	   -- See Note [Avoiding spurious errors]
-       ; when (isEmptyBag implics && null non_ambigs) $
-         reportAmbigErrs ctxt skols ambigs }
+       	   -- Only report ambiguity if no other errors (at all) happened
+	   -- See Note [Avoiding spurious errors] in TcSimplify
+       ; ifErrsM (return ()) $ reportAmbigErrs ctxt skols ambigs }
   where
     skols = foldr (unionVarSet . ic_skols) emptyVarSet (cec_encl ctxt)
  
-- 
1.7.10.4