An abstract NameSpace should only inherit from an abstract NameSpace.
An abstract NameSpace cannot be instantiated. Therefore an abstract NameSpace should not inherit from a NameSpace that can be instantiated because it would inherit instanciable properties.
- Make the child NameSpace concrete.
- Ensure that all parents are abstract.
- You can also consider disabling this rule in the preferences. Many programming languages accept abstract classes inheriting from concrete ones.