patch 9.0.1974: vim9: using contra-variant type-checksv9.0.1974

Problem:  vim9: using contra-variant type-checks (after v9.0.1959)
Solution: Use invariant type checking instead

closes: #13248

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>

1 files changed, 27 insertions, 3 deletions

diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
index 856ee03108..4a92a3d3a2 100644
--- a/src/testdir/test_vim9_class.vim
+++ b/src/testdir/test_vim9_class.vim
@@ -6338,7 +6338,31 @@ def Test_extended_obj_method_type_check()
     endclass
 
     class Bar extends Foo
-      def Doit(p: A): C
+      def Doit(p: C): B
+        return B.new()
+      enddef
+    endclass
+  END
+  v9.CheckSourceFailure(lines, 'E1383: Method "Doit": type mismatch, expected func(object<B>): object<B> but got func(object<C>): object<B>', 20)
+
+  lines =<< trim END
+    vim9script
+
+    class A
+    endclass
+    class B extends A
+    endclass
+    class C extends B
+    endclass
+
+    class Foo
+      def Doit(p: B): B
+        return B.new()
+      enddef
+    endclass
+
+    class Bar extends Foo
+      def Doit(p: B): C
         return C.new()
       enddef
     endclass
@@ -6362,12 +6386,12 @@ def Test_extended_obj_method_type_check()
     endclass
 
     class Bar extends Foo
-      def Doit(p: C): B
+      def Doit(p: A): B
         return B.new()
       enddef
     endclass
   END
-  v9.CheckSourceFailure(lines, 'E1383: Method "Doit": type mismatch, expected func(object<B>): object<B> but got func(object<C>): object<B>', 20)
+  v9.CheckSourceFailure(lines, 'E1383: Method "Doit": type mismatch, expected func(object<B>): object<B> but got func(object<A>): object<B>', 20)
 
   lines =<< trim END
     vim9script