From e228575f7a179ebd3aec94e5ba5ffc74d5c0ec13 Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Thu, 28 Mar 2002 09:59:03 +0000
Subject: [PATCH] [project @ 2002-03-28 09:59:03 by simonmar] The test suite
 wins again: re-enable empty contexts in data declarations.

---
 ghc/compiler/parser/Parser.y |   22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y
index 88c0ad9..35b8854 100644
--- a/ghc/compiler/parser/Parser.y
+++ b/ghc/compiler/parser/Parser.y
@@ -1,6 +1,6 @@
 {-								-*-haskell-*-
 -----------------------------------------------------------------------------
-$Id: Parser.y,v 1.93 2002/03/14 15:47:54 simonmar Exp $
+$Id: Parser.y,v 1.94 2002/03/28 09:59:03 simonmar Exp $
 
 Haskell grammar.
 
@@ -443,15 +443,23 @@ topdecl :: { RdrBinding }
 --	(Eq a, Ord b) => T a b
 -- Rather a lot of inlining here, else we get reduce/reduce errors
 tycl_hdr :: { (RdrNameContext, RdrName, [RdrNameHsTyVar]) }
-	: '(' comma_types1 ')' '=>' gtycon tv_bndrs	{% mapP checkPred $2	`thenP` \ cxt ->
-							   returnP (cxt, $5, $6) }
+	: '(' comma_types1 ')' '=>' gtycon tv_bndrs
+		{% mapP checkPred $2	`thenP` \ cxt ->
+		  returnP (cxt, $5, $6) }
+
+	| '(' ')' '=>' gtycon tv_bndrs
+		{ ([], $4, $5) }
+
           -- qtycon for the class below name would lead to many s/r conflicts
 	  --   FIXME: does the renamer pick up all wrong forms and raise an
 	  --	      error 
-	| gtycon atypes1 '=>' gtycon atypes0		{% checkTyVars $5	`thenP` \ tvs ->
-						  	   returnP ([HsClassP $1 $2], $4, tvs) }
-	| gtycon  atypes0				{% checkTyVars $2	`thenP` \ tvs ->
-						  	   returnP ([], $1, tvs) }
+	| gtycon atypes1 '=>' gtycon atypes0	
+		{% checkTyVars $5	`thenP` \ tvs ->
+		   returnP ([HsClassP $1 $2], $4, tvs) }
+
+	| gtycon  atypes0
+		{% checkTyVars $2	`thenP` \ tvs ->
+		   returnP ([], $1, tvs) }
 		-- We have to have qtycon in this production to avoid s/r
 		-- conflicts with the previous one.  The renamer will complain
 		-- if we use a qualified tycon.
-- 
1.7.10.4