MISRA C++:2008 Rule 10-1-3

An accessible base class shall not be both virtual and non-virtual in the same hierarchy

Description

Rule Definition

An accessible base class shall not be both virtual and non-virtual in the same hierarchy.¹

Rationale

The checker flags situations where the same class is inherited as a virtual base class and a non-virtual base class in the same derived class. These situations defeat the purpose of virtual inheritance and causes multiple copies of the base class sub-object in the derived class object.

Troubleshooting

If you expect a rule violation but Polyspace^® does not report it, see Diagnose Why Coding Standard Violations Do Not Appear as Expected.

Examples

Base Class Both Virtual and Non-Virtual in Same Hierarchy

class Base {};
class Intermediate1: virtual public Base {};
class Intermediate2: virtual public Base {};
class Intermediate3: public Base {};
class Final: public Intermediate1, Intermediate2, Intermediate3 {}; //Noncompliant

In this example, the class Base is inherited in Final both as a virtual and non-virtual base class. The Final object contains at least two copies of a Base sub-object.

Check Information

Group: Derived Classes

Category: Required

Version History

Introduced in R2013b