From: simonpj@microsoft.com <unknown>
Date: Mon, 17 Sep 2007 16:07:08 +0000 (+0000)
Subject: Loosen the syntax of types slightly
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;ds=sidebyside;h=fa1a55badb9e8869f74e4a63c38cf4837e122496;p=ghc-hetmet.git

Loosen the syntax of types slightly

This change allows you to write
	f :: (Eq a) => (Ord b) => a -> b -> b
Previously you could only have a forall and context after '->'
but not after '=>' which is strange and inconsistent.

Making the parser a bit more generous didn't change the number
of shift/reduce conflicts.

tc236 tests.
---

diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index bfd0525..2bfb895 100644
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -971,7 +971,7 @@ gentypedoc :: { LHsType RdrName }
 
 ctypedoc  :: { LHsType RdrName }
         : 'forall' tv_bndrs '.' ctypedoc { LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
-        | context '=>' gentypedoc        { LL $ mkImplicitHsForAllTy   $1 $3 }
+        | context '=>' ctypedoc          { LL $ mkImplicitHsForAllTy   $1 $3 }
 	-- A type of form (context => type) is an *implicit* HsForAllTy
 	| gentypedoc			 { $1 }