From: simonpj <unknown>
Date: Tue, 16 Dec 2003 14:27:31 +0000 (+0000)
Subject: [project @ 2003-12-16 14:27:31 by simonpj]
X-Git-Tag: Approx_11550_changesets_converted~195
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=064a4bf8c981c8fe135a648b08d31f940f5693c6;p=ghc-hetmet.git

[project @ 2003-12-16 14:27:31 by simonpj]
comments only
---

diff --git a/ghc/compiler/coreSyn/CoreUtils.lhs b/ghc/compiler/coreSyn/CoreUtils.lhs
index 67d1610..5111730 100644
--- a/ghc/compiler/coreSyn/CoreUtils.lhs
+++ b/ghc/compiler/coreSyn/CoreUtils.lhs
@@ -793,6 +793,11 @@ arityType (App f a)  	   = case arityType f of
 							   
 	-- Case/Let; keep arity if either the expression is cheap
 	-- or it's a 1-shot lambda
+	-- The former is not really right for Haskell
+	--	f x = case x of { (a,b) -> \y. e }
+	--  ===>
+	--	f x y = case x of { (a,b) -> e }
+	-- The difference is observable using 'seq'
 arityType (Case scrut _ alts) = case foldr1 andArityType [arityType rhs | (_,_,rhs) <- alts] of
 				  xs@(AFun one_shot _) | one_shot -> xs
 				  xs | exprIsCheap scrut	  -> xs