test: cover compatibility YESNO method field assignment

tests/test_validate_typecheck_diagnostics.py

@@ -192,6 +192,12 @@ class ValidateTypecheckDiagnosticsTests(unittest.TestCase):
             MODULE.EXPECTED,
         )
 
+    def test_includes_compatibility_yesno_method_field_assignment_success_fixture(self):
+        self.assertIn(
+            "tests/typecheck_method_compat_yesno_field_assignment_good.claro",
+            MODULE.EXPECTED_OK,
+        )
+
     def test_includes_method_field_check_type_fixtures(self):
         self.assertIn(
             "tests/typecheck_method_field_check_type_bad.claro",

tests/typecheck_method_compat_yesno_field_assignment_good.claro

@@ -0,0 +1,9 @@
+CLASS Player
+    HAS ready YESNO
+    TEACH toggle TAKES value
+        SET ready value
+    LEARNED
+ENDCLASS
+
+NEW Player player
+CALL player.toggle WITH YES