X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcHsType.lhs;h=30a47f7a5d842ed96e3aa5afbbd596e5d47401f4;hp=b7e5b0bee47c56f8f4eac2caa072e75660814946;hb=80c89b80c355b2aaebcd53330e6c6170c3f05aca;hpb=e656c6e3aaa827c51cd39c9cd9f0a6461db1d4c2

diff --git a/compiler/typecheck/TcHsType.lhs b/compiler/typecheck/TcHsType.lhs
index b7e5b0b..30a47f7 100644
--- a/compiler/typecheck/TcHsType.lhs
+++ b/compiler/typecheck/TcHsType.lhs
@@ -24,7 +24,7 @@ module TcHsType (
 #include "HsVersions.h"
 
 import HsSyn		( HsType(..), LHsType, HsTyVarBndr(..), LHsTyVarBndr, 
-			  LHsContext, HsPred(..), LHsPred, HsExplicitForAll(..) )
+			  LHsContext, HsPred(..), LHsPred )
 import RnHsSyn		( extractHsTyVars )
 import TcRnMonad
 import TcEnv		( tcExtendTyVarEnv, tcExtendKindEnvTvs, 
@@ -45,7 +45,7 @@ import TcType		( Type, PredType(..), ThetaType, BoxySigmaType,
 			  substTyWith, mkTyVarTys, tcEqType,
 		 	  tcIsTyVarTy, mkFunTy, mkSigmaTy, mkPredTy, 
 			  mkTyConApp, mkAppTys, typeKind )
-import Kind 		( Kind, isLiftedTypeKind, liftedTypeKind, ubxTupleKind, 
+import {- Kind parts of -} Type 		( Kind, isLiftedTypeKind, liftedTypeKind, ubxTupleKind, 
 			  openTypeKind, argTypeKind, splitKindFunTys )
 import Var		( TyVar, mkTyVar, tyVarName )
 import TyCon		( TyCon, tyConKind )
@@ -191,8 +191,7 @@ kcHsSigType ty 	     = kcTypeType ty
 kcHsLiftedSigType ty = kcLiftedType ty
 
 tcHsKindedType :: LHsType Name -> TcM Type
-  -- Don't do kind checking, nor validity checking, 
-  -- 	but do hoist for-alls to the top
+  -- Don't do kind checking, nor validity checking.
   -- This is used in type and class decls, where kinding is
   -- done in advance, and validity checking is done later
   -- [Validity checking done later because of knot-tying issues.]
@@ -242,15 +241,27 @@ kcCheckHsType (L span ty) exp_kind
 		-- because checkExpectedKind already mentions
 		-- 'ty' by name in any error message
 
-	; checkExpectedKind ty act_kind exp_kind
+	; checkExpectedKind (strip ty) act_kind exp_kind
 	; return (L span ty') }
   where
-	-- Wrap a context around only if we want to
-	-- show that contexts.  Omit invisble ones
-	-- and ones user's won't grok (HsPred p).
-    add_ctxt (HsPredTy p)		    	   thing = thing
-    add_ctxt (HsForAllTy Implicit tvs (L _ []) ty) thing = thing
-    add_ctxt other_ty thing = addErrCtxt (typeCtxt ty) thing
+	-- Wrap a context around only if we want to show that contexts.  
+    add_ctxt (HsPredTy p)		 thing = thing
+	-- Omit invisble ones and ones user's won't grok (HsPred p).
+    add_ctxt (HsForAllTy _ _ (L _ []) _) thing = thing
+	-- Omit wrapping if the theta-part is empty
+	-- Reason: the recursive call to kcLiftedType, in the ForAllTy
+	--	   case of kc_hs_type, will do the wrapping instead
+	--	   and we don't want to duplicate
+    add_ctxt other_ty thing = addErrCtxt (typeCtxt other_ty) thing
+
+	-- We infer the kind of the type, and then complain if it's
+	-- not right.  But we don't want to complain about
+	--	(ty) or !(ty) or forall a. ty
+	-- when the real difficulty is with the 'ty' part.
+    strip (HsParTy (L _ ty))          = strip ty
+    strip (HsBangTy _ (L _ ty))       = strip ty
+    strip (HsForAllTy _ _ _ (L _ ty)) = strip ty
+    strip ty			      = ty
 \end{code}
 
 	Here comes the main function
@@ -326,17 +337,18 @@ kc_hs_type (HsPredTy pred)
 
 kc_hs_type (HsForAllTy exp tv_names context ty)
   = kcHsTyVars tv_names		$ \ tv_names' ->
-    kcHsContext context		`thenM`	\ ctxt' ->
-    kcLiftedType ty		`thenM` \ ty' ->
-	-- The body of a forall is usually a type, but in principle
-	-- there's no reason to prohibit *unlifted* types.
-	-- In fact, GHC can itself construct a function with an
-	-- unboxed tuple inside a for-all (via CPR analyis; see 
-	-- typecheck/should_compile/tc170)
-	--
-	-- Still, that's only for internal interfaces, which aren't
-	-- kind-checked, so we only allow liftedTypeKind here
-    returnM (HsForAllTy exp tv_names' ctxt' ty', liftedTypeKind)
+    do	{ ctxt' <- kcHsContext context
+	; ty'   <- kcLiftedType ty
+	     -- The body of a forall is usually a type, but in principle
+	     -- there's no reason to prohibit *unlifted* types.
+	     -- In fact, GHC can itself construct a function with an
+	     -- unboxed tuple inside a for-all (via CPR analyis; see 
+	     -- typecheck/should_compile/tc170)
+	     --
+	     -- Still, that's only for internal interfaces, which aren't
+	     -- kind-checked, so we only allow liftedTypeKind here
+
+  	; return (HsForAllTy exp tv_names' ctxt' ty', liftedTypeKind) }
 
 kc_hs_type (HsBangTy b ty)
   = do { (ty', kind) <- kcHsType ty
@@ -494,6 +506,8 @@ ds_type full_ty@(HsForAllTy exp tv_names ctxt ty)
     dsHsType ty				`thenM` \ tau ->
     returnM (mkSigmaTy tyvars theta tau)
 
+ds_type (HsSpliceTy {}) = panic "ds_type: HsSpliceTy"
+
 dsHsTypes arg_tys = mappM dsHsType arg_tys
 \end{code}
 
@@ -616,7 +630,8 @@ tcDataKindSig :: Maybe Kind -> TcM [TyVar]
 -- GADT decls can have a (perhaps partial) kind signature
 --	e.g.  data T :: * -> * -> * where ...
 -- This function makes up suitable (kinded) type variables for 
--- the argument kinds, and checks that the result kind is indeed *
+-- the argument kinds, and checks that the result kind is indeed *.
+-- We use it also to make up argument type variables for for data instances.
 tcDataKindSig Nothing = return []
 tcDataKindSig (Just kind)
   = do	{ checkTc (isLiftedTypeKind res_kind) (badKindSig kind)