X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcRnTypes.lhs;h=ebf410169c8c29c8aaf0769d01fc768125bb9cd1;hp=3e63827b4155a79f0d19ff33b06b8279bad2bba7;hb=7539ed8cade66d09fae1e0ccc66c519cafa3b55b;hpb=55d32c4ca056b509b63a35b0661724e8a2529aee

diff --git a/compiler/typecheck/TcRnTypes.lhs b/compiler/typecheck/TcRnTypes.lhs
index 3e63827..ebf4101 100644
--- a/compiler/typecheck/TcRnTypes.lhs
+++ b/compiler/typecheck/TcRnTypes.lhs
@@ -730,7 +730,8 @@ than with the Avails handling stuff in TcSimplify
 
 \begin{code}
 instance Ord Inst where
-  compare = cmpInst
+   compare = cmpInst
+	-- Used *only* for AvailEnv in TcSimplify
 
 instance Eq Inst where
   (==) i1 i2 = case i1 `cmpInst` i2 of
@@ -761,11 +762,12 @@ cmpInst i1@(ImplicInst {}) i2@(ImplicInst {}) = tci_name i1 `compare` tci_name i
 cmpInst (ImplicInst {})    _                  = LT
 
 	-- same for Equality constraints
-cmpInst (EqInst {})    (Dict {})	      = GT
-cmpInst (EqInst {})    (Method {})	      = GT
-cmpInst (EqInst {})    (LitInst {})	      = GT
-cmpInst (EqInst {})    (ImplicInst {})	      = GT
-cmpInst i1@(EqInst {}) i2@(EqInst {})         = tci_name i1 `compare` tci_name i2
+cmpInst (EqInst {})    (Dict {})       = GT
+cmpInst (EqInst {})    (Method {})     = GT
+cmpInst (EqInst {})    (LitInst {})    = GT
+cmpInst (EqInst {})    (ImplicInst {}) = GT
+cmpInst i1@(EqInst {}) i2@(EqInst {})  = (tci_left  i1 `tcCmpType` tci_left  i2) `thenCmp`
+                                         (tci_right i1 `tcCmpType` tci_right i2)
 \end{code}