X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FcoreSyn%2FCoreSyn.lhs;h=4ec954ce6a5b6282abc0438cb7ecb5aeecc3050b;hb=c6eadadbefe2ec5709e9d31893f79c4ff78754b4;hp=9b9d8faefdfba4b35967d8bd72daa587defdfeba;hpb=ec81fddea750b1ad21f63b7c4307c15f89f10dfd;p=ghc-hetmet.git

diff --git a/compiler/coreSyn/CoreSyn.lhs b/compiler/coreSyn/CoreSyn.lhs
index 9b9d8fae..4ec954c 100644
--- a/compiler/coreSyn/CoreSyn.lhs
+++ b/compiler/coreSyn/CoreSyn.lhs
@@ -228,8 +228,13 @@ data CoreRule
 	ru_name :: RuleName,	-- and suchlike.  It has no free variables.
 	ru_fn :: Name,		-- Name of the Id at 
 				-- the head of this rule
-	ru_nargs :: Int,	-- Number of args that ru_try expects
+	ru_nargs :: Int,	-- Number of args that ru_try expects,
+				-- including type args
 	ru_try  :: [CoreExpr] -> Maybe CoreExpr }
+		-- This function does the rewrite.  It given too many
+		-- arguments, it simply discards them; the returned CoreExpr
+		-- is just the rewrite of ru_fn applied to the first ru_nargs args
+		-- See Note [Extra args in rule matching] in Rules.lhs
 
 isBuiltinRule (BuiltinRule {}) = True
 isBuiltinRule _		       = False