X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcDeriv.lhs;h=82a6d2633288aeb94a6530fe49729094e8c5b69e;hb=cb90040a7e66ca608fec5cee59c3bd137c8b266c;hp=938d55cac3db6afd5bff5bc7e51f36181d89ccd9;hpb=4ff9f4f86846ef2b7231530b8d84c7d568a3e07c;p=ghc-hetmet.git

diff --git a/ghc/compiler/typecheck/TcDeriv.lhs b/ghc/compiler/typecheck/TcDeriv.lhs
index 938d55c..82a6d26 100644
--- a/ghc/compiler/typecheck/TcDeriv.lhs
+++ b/ghc/compiler/typecheck/TcDeriv.lhs
@@ -49,7 +49,7 @@ import Var		( TyVar, tyVarKind, idType, varName )
 import VarSet		( mkVarSet, subVarSet )
 import PrelNames
 import SrcLoc		( srcLocSpan, Located(..) )
-import Util		( zipWithEqual, sortLt, notNull )
+import Util		( zipWithEqual, sortLe, notNull )
 import ListSetOps	( removeDups,  assocMaybe )
 import Outputable
 import Bag
@@ -529,9 +529,10 @@ mkDataTypeEqn tycon clas
 	-- 	  data T a b = ... deriving( Typeable )
 	-- gives
 	--	  instance Typeable2 T where ...
+	-- Notice that:
 	-- 1. There are no constraints in the instance
 	-- 2. There are no type variables either
-	-- 2. The actual class we want to generate isn't necessarily
+	-- 3. The actual class we want to generate isn't necessarily
 	--	Typeable; it depends on the arity of the type
     do	{ real_clas <- tcLookupClass (typeableClassNames !! tyConArity tycon)
 	; dfun_name <- new_dfun_name real_clas tycon
@@ -713,7 +714,7 @@ solveDerivEqns orig_eqns
       = addSrcSpan (srcLocSpan (getSrcLoc tc))		$
 	addErrCtxt (derivCtxt (Just clas) tc)	$
 	tcSimplifyDeriv tyvars deriv_rhs	`thenM` \ theta ->
-	returnM (sortLt (<) theta)	-- Canonicalise before returning the soluction
+	returnM (sortLe (<=) theta)	-- Canonicalise before returning the soluction
 
 mk_deriv_dfun (dfun_name, clas, tycon, tyvars, _) theta
   = mkDictFunId dfun_name tyvars theta