From 73b92b542bb06d33cffd0f548603dd0a4872294a Mon Sep 17 00:00:00 2001
From: simonpj <unknown>
Date: Mon, 30 Apr 2001 10:49:38 +0000
Subject: [PATCH] [project @ 2001-04-30 10:49:38 by simonpj] Add comments

---
 ghc/compiler/typecheck/TcSimplify.lhs |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/ghc/compiler/typecheck/TcSimplify.lhs b/ghc/compiler/typecheck/TcSimplify.lhs
index a4f6af4..d8c3194 100644
--- a/ghc/compiler/typecheck/TcSimplify.lhs
+++ b/ghc/compiler/typecheck/TcSimplify.lhs
@@ -324,6 +324,15 @@ URK!  Let's not do this. So this is illegal:
 	f :: Int -> Int
 	f x = x + ?y
 
+There's a nasty corner case when the monomorphism restriction bites:
+
+	f = x + ?y
+
+The argument above suggests that we must generalise over the ?y parameter, 
+but the monomorphism restriction says that we can't.  The current 
+implementation chooses to let the monomorphism restriction 'win' in this
+case, but it's not clear what the Right Thing is.
+
 BOTTOM LINE: you *must* quantify over implicit parameters.
 
 
-- 
1.7.10.4