From: simonpj@microsoft.com <unknown>
Date: Thu, 23 Feb 2006 14:21:01 +0000 (+0000)
Subject: Comment wibbles
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=3d8ae1e7ba9f238959ca5395b17c485eda5d70e9

Comment wibbles
---

diff --git a/ghc/compiler/typecheck/TcMType.lhs b/ghc/compiler/typecheck/TcMType.lhs
index b306d86..fa129d3 100644
--- a/ghc/compiler/typecheck/TcMType.lhs
+++ b/ghc/compiler/typecheck/TcMType.lhs
@@ -1137,14 +1137,19 @@ Termination test: each assertion in the context satisfies
  (2) the assertion has fewer constructors and variables (taken together
      and counting repetitions) than the head.
 This is only needed with -fglasgow-exts, as Haskell 98 restrictions
-(which have already been checked) guarantee termination.
+(which have already been checked) guarantee termination. 
+
+The underlying idea is that 
+
+    for any ground substitution, each assertion in the
+    context has fewer type constructors than the head.
+
 
 \begin{code}
 checkInstTermination :: ThetaType -> [TcType] -> TcM ()
 checkInstTermination theta tys
-  = do
-    mappM_ (check_nomore (fvTypes tys)) theta
-    mappM_ (check_smaller (sizeTypes tys)) theta
+  = do	{ mappM_ (check_nomore (fvTypes tys))    theta
+	; mappM_ (check_smaller (sizeTypes tys)) theta }
 
 check_nomore :: [TyVar] -> PredType -> TcM ()
 check_nomore fvs pred