From f4af918f1c71daebd6a3a9b2f26fd80326400dab Mon Sep 17 00:00:00 2001
From: "simonpj@microsoft.com" <unknown>
Date: Wed, 11 Feb 2009 09:40:28 +0000
Subject: [PATCH] Turn another ASSERT into a WARN (temproraily)

Fix Trac #3011 by temporarily making it only a WARN if we assign twice
to the same unification variable.
---
 compiler/typecheck/TcMType.lhs |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/compiler/typecheck/TcMType.lhs b/compiler/typecheck/TcMType.lhs
index 75ce6c9..47592f5 100644
--- a/compiler/typecheck/TcMType.lhs
+++ b/compiler/typecheck/TcMType.lhs
@@ -523,7 +523,12 @@ writeMetaTyVar tyvar ty
   = ASSERT( isMetaTyVar tyvar )
     -- TOM: It should also work for coercions
     -- ASSERT2( k2 `isSubKind` k1, (ppr tyvar <+> ppr k1) $$ (ppr ty <+> ppr k2) )
-    do	{ ASSERTM2( do { details <- readMetaTyVar tyvar; return (isFlexi details) }, ppr tyvar )
+    do	{ if debugIsOn then do { details <- readMetaTyVar tyvar; 
+    	     	       	       ; WARN( not (isFlexi details), ppr tyvar )
+			       	 return () }
+			else return () 
+		-- Temporarily make this a warning, until we fix Trac #2999
+
 	; traceTc (text "writeMetaTyVar" <+> ppr tyvar <+> text ":=" <+> ppr ty)
 	; writeMutVar (metaTvRef tyvar) (Indirect ty) }
   where
-- 
1.7.10.4