Based on my research, I understand the issue. The `TypeSerializer` class in Django's migration serializer uses `__name__` instead of `__qualname__`, which causes incorrect paths for inner/nested classes. The fix is to replace `__name__` with `__qualname__` in two places within the `TypeSerializer.serialize()` method.

--- a/django/db/migrations/serializer.py
+++ b/django/db/migrations/serializer.py
@@ -268,9 +268,9 @@ class TypeSerializer(BaseSerializer):
             if self.value is case:
                 return string, set(imports)
         if hasattr(self.value, "__module__"):
             module = self.value.__module__
             if module == builtins.__name__:
-                return self.value.__name__, set()
+                return self.value.__qualname__, set()
             else:
-                return "%s.%s" % (module, self.value.__name__), {"import %s" % module}
+                return "%s.%s" % (module, self.value.__qualname__), {"import %s" % module}
         raise ValueError(
             "Cannot serialize type: %s" % self.value.__name__