[project @ 2004-04-05 07:54:39 by simonpj]

Fix parsing bug in new deriving stuff, which was killing the HEAD

diff --git a/ghc/compiler/parser/Parser.y.pp b/ghc/compiler/parser/Parser.y.pp
index 49eefb3..dbe8eb6 100644 (file)
--- a/ghc/compiler/parser/Parser.y.pp
+++ b/ghc/compiler/parser/Parser.y.pp
@@ -898,8 +898,15 @@ strict_mark :: { Located HsBang }
        : '!'                           { L1 HsStrict }
        | '{-# UNPACK' '#-}' '!'        { LL HsUnbox }
 
+-- We allow the odd-looking 'inst_type' in a deriving clause, so that
+-- we can do deriving( forall a. C [a] ) in a newtype (GHC extension).
+-- The 'C [a]' part is converted to an HsPredTy by checkInstType
+-- We don't allow a context, but that's sorted out by the type checker.
 deriving :: { Located (Maybe [LHsType RdrName]) }
        : {- empty -}                           { noLoc Nothing }
+       | 'deriving' qtycon     {% do { let { L loc tv = $2 }
+                                     ; p <- checkInstType (L loc (HsTyVar tv))
+                                     ; return (LL (Just [p])) } }
        | 'deriving' '(' ')'                    { LL (Just []) }
        | 'deriving' '(' inst_types1 ')'        { LL (Just $3) }
              -- Glasgow extension: allow partial