Added parser and abstract syntax support for stand-alone deriving declarations.

[ghc-hetmet.git] / compiler / parser / RdrHsSyn.lhs

diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs
index ace6fd0..7373ec0 100644 (file)
--- a/compiler/parser/RdrHsSyn.lhs
+++ b/compiler/parser/RdrHsSyn.lhs
@@ -40,6 +40,7 @@ module RdrHsSyn (
        checkSynHdr,          -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName])
        checkKindSigs,        -- [LTyClDecl RdrName] -> P ()
        checkInstType,        -- HsType -> P HsType
+        checkDerivDecl,       -- LDerivDecl RdrName -> P (LDerivDecl RdrName)
        checkPattern,         -- HsExp -> P HsPat
        checkPatterns,        -- SrcLoc -> [HsExp] -> P [HsPat]
        checkDo,              -- [Stmt] -> P [Stmt]
@@ -56,7 +57,7 @@ import RdrName                ( RdrName, isRdrTyVar, mkUnqual, rdrNameOcc,
                          isRdrDataCon, isUnqual, getRdrName, isQual,
                          setRdrNameSpace )
 import BasicTypes      ( maxPrecedence, Activation, InlineSpec(..), alwaysInlineSpec, neverInlineSpec )
-import Lexer           ( P, failSpanMsgP, extension, bangPatEnabled )
+import Lexer           ( P, failSpanMsgP, extension, glaExtsEnabled, bangPatEnabled )
 import TysWiredIn      ( unitTyCon ) 
 import ForeignCall     ( CCallConv, Safety, CCallTarget(..), CExportSpec(..),
                          DNCallSpec(..), DNKind(..), CLabelString )
@@ -559,6 +560,16 @@ checkDictTy (L spn ty) = check ty []
   check (HsParTy t)   args = check (unLoc t) args
   check _ _ = parseError spn "Malformed context in instance header"
 
+
+---------------------------------------------------------------------------
+-- Checking stand-alone deriving declarations
+
+checkDerivDecl :: LDerivDecl RdrName -> P (LDerivDecl RdrName)
+checkDerivDecl d@(L loc _) = 
+    do glaExtOn <- extension glaExtsEnabled
+       if glaExtOn then return d
+        else parseError loc "Illegal stand-alone deriving declaration (use -fglasgow-exts)"
+
 ---------------------------------------------------------------------------
 -- Checking statements in a do-expression
 --     We parse   do { e1 ; e2 ; }