[project @ 2005-04-16 22:45:17 by simonpj]

Improve location info for kind errors; may make some tests change their output

diff --git a/ghc/compiler/typecheck/TcHsType.lhs b/ghc/compiler/typecheck/TcHsType.lhs
index fb9f0db..6686899 100644 (file)
--- a/ghc/compiler/typecheck/TcHsType.lhs
+++ b/ghc/compiler/typecheck/TcHsType.lhs
@@ -39,9 +39,8 @@ import TcUnify                ( unifyFunKind, checkExpectedKind )
 import TcType          ( Type, PredType(..), ThetaType, 
                          MetaDetails(Flexi), hoistForAllTys,
                          TcType, TcTyVar, TcKind, TcThetaType, TcTauType,
-                         mkFunTy, 
-                         mkSigmaTy, mkPredTy, mkGenTyConApp, mkTyConApp, mkAppTys, 
-                         typeKind )
+                         mkFunTy, mkSigmaTy, mkPredTy, mkGenTyConApp, 
+                         mkTyConApp, mkAppTys, typeKind )
 import Kind            ( Kind, isLiftedTypeKind, liftedTypeKind, ubxTupleKind, 
                          openTypeKind, argTypeKind, splitKindFunTys )
 import Id              ( idName )
@@ -238,9 +237,13 @@ kcCheckHsType :: LHsType Name -> TcKind -> TcM (LHsType Name)
 -- with OpenTypeKind, because it gives better error messages
 kcCheckHsType (L span ty) exp_kind 
   = setSrcSpan span                            $
-    kc_hs_type ty                              `thenM` \ (ty', act_kind) ->
-    checkExpectedKind ty act_kind exp_kind     `thenM_`
-    returnM (L span ty')
+    do { (ty', act_kind) <- addErrCtxt (typeCtxt ty) $
+                            kc_hs_type ty
+               -- Add the context round the inner check only
+               -- because checkExpectedKind already mentions
+               -- 'ty' by name in any error message
+       ; checkExpectedKind ty act_kind exp_kind
+       ; return (L span ty') }
 \end{code}
 
        Here comes the main function
@@ -576,6 +579,8 @@ gadtSigCtxt ty
 badGadtDecl ty
   = hang (ptext SLIT("Malformed constructor signature:"))
        2 (ppr ty)
+
+typeCtxt ty = ptext SLIT("In the type") <+> quotes (ppr ty)
 \end{code}
 
 %************************************************************************