From: simonpj <unknown>
Date: Thu, 20 Dec 2001 17:09:46 +0000 (+0000)
Subject: [project @ 2001-12-20 17:09:46 by simonpj]
X-Git-Tag: Approximately_9120_patches~358
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=e8e3d26451f769461d786d58ddf48fe2c3a687fd;p=ghc-hetmet.git

[project @ 2001-12-20 17:09:46 by simonpj]
Comments
---

diff --git a/ghc/compiler/types/Type.lhs b/ghc/compiler/types/Type.lhs
index 056316d..c561acb 100644
--- a/ghc/compiler/types/Type.lhs
+++ b/ghc/compiler/types/Type.lhs
@@ -958,6 +958,16 @@ seqPred (IParam n ty)  = n  `seq` seqType ty
 Comparison; don't use instances so that we know where it happens.
 Look through newtypes but not usage types.
 
+Note that eqType can respond 'False' for partial applications of newtypes.
+Consider
+	newtype Parser m a = MkParser (Foogle m a)
+
+Does 	
+	Monad (Parser m) `eqType` Monad (Foogle m)
+
+Well, yes, but eqType won't see that they are the same. 
+I don't think this is harmful, but it's soemthing to watch out for.
+
 \begin{code}
 eqType t1 t2 = eq_ty emptyVarEnv t1 t2
 eqKind  = eqType	-- No worries about looking