[project @ 2005-03-16 09:04:26 by simonpj]

----------------------------------
 	Two GADT error-reporting bugs
	----------------------------------

	Merge to STABLE

...missed file...

1.  Bug in kind-checking for GADTs; turned out to be in
    isOpenTypeKind on KindVars

....

diff --git a/ghc/compiler/types/Kind.lhs b/ghc/compiler/types/Kind.lhs
index db7fe9a..191dd41 100644 (file)
--- a/ghc/compiler/types/Kind.lhs
+++ b/ghc/compiler/types/Kind.lhs
@@ -145,6 +145,9 @@ isArgTypeKind other        = False
 isOpenTypeKind :: Kind -> Bool
 -- True of any sub-kind of OpenTypeKind (i.e. anything except arrow)
 isOpenTypeKind (FunKind _ _) = False
+isOpenTypeKind (KindVar _)   = False   -- This is a conservative answer
+                                       -- It matters in the call to isSubKind in
+                                       -- checkExpectedKind.
 isOpenTypeKind other        = True
 
 isSubKind :: Kind -> Kind -> Bool
@@ -154,9 +157,8 @@ isSubKind UnliftedTypeKind UnliftedTypeKind = True
 isSubKind UbxTupleKind     UbxTupleKind     = True
 isSubKind k1              OpenTypeKind     = isOpenTypeKind k1
 isSubKind k1              ArgTypeKind      = isArgTypeKind k1
-isSubKind (FunKind a1 r1) (FunKind a2 r2)
-  = (a2 `isSubKind` a1) && (r1 `isSubKind` r2)
-isSubKind k1 k2 = False
+isSubKind (FunKind a1 r1) (FunKind a2 r2)   = (a2 `isSubKind` a1) && (r1 `isSubKind` r2)
+isSubKind k1             k2                = False
 
 defaultKind :: Kind -> Kind
 -- Used when generalising: default kind '?' and '??' to '*'