X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fspecialise%2FRules.lhs;h=000df944cfcc1907447b9fcc7ebb63a73a74b671;hb=9367b24fde0c3f5efa5934e69571f5834ed43548;hp=65975f81cb537372135332c1b567c558775ff8a7;hpb=df62fe193785e1fc9786a6c7321670f99fa9a37d;p=ghc-hetmet.git

diff --git a/compiler/specialise/Rules.lhs b/compiler/specialise/Rules.lhs
index 65975f8..000df94 100644
--- a/compiler/specialise/Rules.lhs
+++ b/compiler/specialise/Rules.lhs
@@ -123,11 +123,13 @@ ruleCantMatch :: [Maybe Name] -> [Maybe Name] -> Bool
 -- It's only a one-way match; unlike instance matching we 
 -- don't consider unification
 -- 
--- Notice that there is no case
---	ruleCantMatch (Just n1 : ts) (Nothing : as) = True
--- Reason: a local variable 'v' in the actuals might 
--- 	   have an unfolding which is a global.
---	   This quite often happens with case scrutinees.
+-- Notice that [_$_]
+--	ruleCantMatch [Nothing] [Just n2] = False
+--      Reason: a template variable can be instantiated by a constant
+-- Also:
+--	ruleCantMatch [Just n1] [Nothing] = False
+--      Reason: a local variable 'v' in the actuals might [_$_]
+
 ruleCantMatch (Just n1 : ts) (Just n2 : as) = n1 /= n2 || ruleCantMatch ts as
 ruleCantMatch (t       : ts) (a       : as) = ruleCantMatch ts as
 ruleCantMatch ts	     as		    = False
@@ -273,10 +275,10 @@ findBest target (rule1,ans1) ((rule2,ans2):prs)
 			| otherwise          = doubleQuotes (ftext (ru_name rule))
 		in pprTrace "Rules.findBest: rule overlap (Rule 1 wins)"
 			 (vcat [if opt_PprStyle_Debug then 
-				   ptext SLIT("Expression to match:") <+> ppr fn <+> sep (map ppr args)
+				   ptext (sLit "Expression to match:") <+> ppr fn <+> sep (map ppr args)
 				else empty,
-				ptext SLIT("Rule 1:") <+> pp_rule rule1, 
-				ptext SLIT("Rule 2:") <+> pp_rule rule2]) $
+				ptext (sLit "Rule 1:") <+> pp_rule rule1, 
+				ptext (sLit "Rule 2:") <+> pp_rule rule2]) $
 		findBest target (rule1,ans1) prs
   | otherwise = findBest target (rule1,ans1) prs
   where
@@ -830,9 +832,9 @@ ruleAppCheck_help phase fn args rules
     check_rule rule = rule_herald rule <> colon <+> rule_info rule
 
     rule_herald (BuiltinRule { ru_name = name })
-	= ptext SLIT("Builtin rule") <+> doubleQuotes (ftext name)
+	= ptext (sLit "Builtin rule") <+> doubleQuotes (ftext name)
     rule_herald (Rule { ru_name = name })
-	= ptext SLIT("Rule") <+> doubleQuotes (ftext name)
+	= ptext (sLit "Rule") <+> doubleQuotes (ftext name)
 
     rule_info rule
 	| Just _ <- matchRule noBlackList emptyInScopeSet args rough_args rule