X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=compiler%2Fparser%2FRdrHsSyn.lhs;h=4c1da58d8f7af458c28425fa73493e778f969479;hb=4186a2d5ae04d985fe141a8701fd75d05760f7f7;hp=ae4a15a2a1c29eafc0f0940978ba0c2e3d77546a;hpb=0a5613f40b0e32cf59966e6b56b807cdbe80aa7b;p=ghc-hetmet.git

diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs
index ae4a15a..4c1da58 100644
--- a/compiler/parser/RdrHsSyn.lhs
+++ b/compiler/parser/RdrHsSyn.lhs
@@ -70,6 +70,7 @@ import FastString
 import Maybes
 
 import Control.Applicative ((<$>))       
+import Control.Monad
 import Text.ParserCombinators.ReadP as ReadP
 import Data.List        ( nubBy )
 import Data.Char
@@ -172,13 +173,14 @@ Similarly for mkConDecl, mkClassOpSig and default-method names.
   
 \begin{code}
 mkClassDecl :: SrcSpan
-            -> Located (LHsContext RdrName, LHsType RdrName) 
+            -> Located (Maybe (LHsContext RdrName), LHsType RdrName)
             -> Located [Located (FunDep RdrName)]
             -> Located (OrdList (LHsDecl RdrName))
 	    -> P (LTyClDecl RdrName)
 
-mkClassDecl loc (L _ (cxt, tycl_hdr)) fds where_cls
+mkClassDecl loc (L _ (mcxt, tycl_hdr)) fds where_cls
   = do { let (binds, sigs, ats, docs) = cvBindsAndSigs (unLoc where_cls)
+       ; let cxt = fromMaybe (noLoc []) mcxt
        ; (cls, tparams) <- checkTyClHdr tycl_hdr
        ; tyvars <- checkTyVars tparams      -- Only type vars allowed
        ; checkKindSigs ats
@@ -189,14 +191,16 @@ mkClassDecl loc (L _ (cxt, tycl_hdr)) fds where_cls
 mkTyData :: SrcSpan
          -> NewOrData
 	 -> Bool		-- True <=> data family instance
-         -> Located (LHsContext RdrName, LHsType RdrName)
+         -> Located (Maybe (LHsContext RdrName), LHsType RdrName)
          -> Maybe Kind
          -> [LConDecl RdrName]
          -> Maybe [LHsType RdrName]
          -> P (LTyClDecl RdrName)
-mkTyData loc new_or_data is_family (L _ (cxt, tycl_hdr)) ksig data_cons maybe_deriv
+mkTyData loc new_or_data is_family (L _ (mcxt, tycl_hdr)) ksig data_cons maybe_deriv
   = do { (tc, tparams) <- checkTyClHdr tycl_hdr
 
+       ; checkDatatypeContext mcxt
+       ; let cxt = fromMaybe (noLoc []) mcxt
        ; (tyvars, typats) <- checkTParams is_family tparams
        ; return (L loc (TyData { tcdND = new_or_data, tcdCtxt = cxt, tcdLName = tc,
 	                  	 tcdTyVars = tyvars, tcdTyPats = typats, 
@@ -231,8 +235,8 @@ mkTopSpliceDecl :: LHsExpr RdrName -> HsDecl RdrName
 --      f x            then behave as if she'd written $(f x)
 --		       ie a SpliceD
 mkTopSpliceDecl (L _ (HsQuasiQuoteE qq))            = QuasiQuoteD qq
-mkTopSpliceDecl (L _ (HsSpliceE (HsSplice _ expr))) = SpliceD (SpliceDecl expr)
-mkTopSpliceDecl other_expr                          = SpliceD (SpliceDecl other_expr)
+mkTopSpliceDecl (L _ (HsSpliceE (HsSplice _ expr))) = SpliceD (SpliceDecl expr       Explicit)
+mkTopSpliceDecl other_expr                          = SpliceD (SpliceDecl other_expr Implicit)
 \end{code}
 
 %************************************************************************
@@ -521,6 +525,13 @@ checkTyVars tparms = mapM chk tparms
     chk (L l _)            =
 	  parseError l "Type found where type variable expected"
 
+checkDatatypeContext :: Maybe (LHsContext RdrName) -> P ()
+checkDatatypeContext Nothing = return ()
+checkDatatypeContext (Just (L loc _))
+    = do allowed <- extension datatypeContextsEnabled
+         unless allowed $
+             parseError loc "Illegal datatype context (use -XDatatypeContexts)"
+
 checkTyClHdr :: LHsType RdrName
              -> P (Located RdrName,	     -- the head symbol (type or class name)
 	           [LHsType RdrName])        -- parameters of head symbol
@@ -788,12 +799,14 @@ checkValSig
 checkValSig (L l (HsVar v)) ty 
   | isUnqual v && not (isDataOcc (rdrNameOcc v))
   = return (TypeSig (L l v) ty)
-checkValSig lhs@(L l _)         _
-  | looks_like_foreign lhs
-  = parseError l "Invalid type signature; perhaps you meant to use -XForeignFunctionInterface?"
-  | otherwise
-  = parseError l "Invalid type signature: should be of form <variable> :: <type>"
+checkValSig lhs@(L l _) ty
+  = parseErrorSDoc l ((text "Invalid type signature:" <+>
+                       ppr lhs <+> text "::" <+> ppr ty)
+                   $$ text hint)
   where
+    hint = if looks_like_foreign lhs
+           then "Perhaps you meant to use -XForeignFunctionInterface?"
+           else "Should be of form <variable> :: <type>"
     -- A common error is to forget the ForeignFunctionInterface flag
     -- so check for that, and suggest.  cf Trac #3805
     -- Sadly 'foreign import' still barfs 'parse error' because 'import' is a keyword