diff --git a/mypy_self_check.ini b/mypy_self_check.ini
index d4c0e8445f48..f54c1f17f025 100644
--- a/mypy_self_check.ini
+++ b/mypy_self_check.ini
@@ -1,6 +1,7 @@
 [mypy]
 
 strict = True
+local_partial_types = True
 disallow_any_unimported = True
 show_traceback = True
 pretty = True
diff --git a/test-data/unit/plugins/dyn_class.py b/test-data/unit/plugins/dyn_class.py
index 18e948e3dd2a..1471267b24ee 100644
--- a/test-data/unit/plugins/dyn_class.py
+++ b/test-data/unit/plugins/dyn_class.py
@@ -6,7 +6,7 @@
 from mypy.plugin import ClassDefContext, DynamicClassDefContext, Plugin
 from mypy.types import Instance, get_proper_type
 
-DECL_BASES = set()
+DECL_BASES: set[str] = set()
 
 
 class DynPlugin(Plugin):