Rule 10-3-1

[wcarl]

There shall be no more than one definition of each virtual function on each path through the inheritance hierarchy.

If I'm interpreting this rule correctly, once you define a virtual function for a derived class with the virtual base class as an ancestor, no more derivations in the chain can override the first definition.

This would seem to cripple a key advantage of using classes and an object-oriented design.

Isn't it pretty common to override a virtual member function in a child class even if the parent class has provided a different definition? Please explain.

[misra cpp]

This is intentional and, as stated in the text for the rule, is done to increase clarity for review and maintenance. It would be acceptable to deviate if a more complex hierarchy is required.

We will review this when working on the next version of MISRA C++.

[dg1980]

Under the impression of MISRA Compliance i came up with two deviation permits so far:

• Reliability (Fault tolerance): Implementing default/fallback behaviour/strategy for polymorphic types
  
• Maintainability (Reusability): Extending base class functionality for polymorphic types

[misra cpp]

Thanks