X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcSimplify.lhs;h=8632895b10893c194b036a2ab034c8f7490d6d0c;hb=58521c72cec262496dabf5fffb057d25ab17a0f7;hp=11e202be9b3e57ecfa8e86a58ecfc16bb367eb78;hpb=9d0c8f842e35dde3d570580cf62a32779f66a6de;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcSimplify.lhs b/compiler/typecheck/TcSimplify.lhs
index 11e202b..8632895 100644
--- a/compiler/typecheck/TcSimplify.lhs
+++ b/compiler/typecheck/TcSimplify.lhs
@@ -45,7 +45,6 @@ import Class
 import FunDeps
 import PrelInfo
 import PrelNames
-import Type
 import TysWiredIn
 import ErrUtils
 import BasicTypes
@@ -54,7 +53,6 @@ import VarEnv
 import FiniteMap
 import Bag
 import Outputable
-import Maybes
 import ListSetOps
 import Util
 import SrcLoc
@@ -1589,13 +1587,23 @@ Simpler, maybe, but alas not simple (see Trac #2494)
 tcSimplifyRuleLhs :: [Inst] -> TcM ([Inst], TcDictBinds)
 tcSimplifyRuleLhs wanteds
   = do	{ wanteds' <- zonkInsts wanteds
-	; (irreds, binds) <- go [] emptyBag wanteds'
+    	
+		-- Simplify equalities  
+		-- It's important to do this: Trac #3346 for example
+        ; (_, wanteds'', tybinds, binds1) <- tcReduceEqs [] wanteds'
+        ; execTcTyVarBinds tybinds
+
+	  	-- Simplify other constraints
+	; (irreds, binds2) <- go [] emptyBag wanteds''
+
+	  	-- Report anything that is left
 	; let (dicts, bad_irreds) = partition isDict irreds
 	; traceTc (text "tcSimplifyrulelhs" <+> pprInsts bad_irreds)
 	; addNoInstanceErrs (nub bad_irreds)
 		-- The nub removes duplicates, which has
 		-- not happened otherwise (see notes above)
-	; return (dicts, binds) }
+
+	; return (dicts, binds1 `unionBags` binds2) }
   where
     go :: [Inst] -> TcDictBinds -> [Inst] -> TcM ([Inst], TcDictBinds)
     go irreds binds []