On 2026-10-14, Remy Porter reported a C++ anecdote involving Mandy's coworker. The coworker had adopted virtual inheritance as a default rule and used it consistently.

Virtual inheritance addresses the diamond problem in multiple inheritance. A is the base class. B and C derive from A, while D derives from both. Without virtual inheritance, D contains two internal copies of A and its members. With `class B : public virtual A`, D receives a single copy of A. The mechanism matters only when a class has derived classes.

That condition is absent from the example. `SomeSpecificDerivedClass` is declared `final`, so no class can inherit from it. Adding `virtual` to its inheritance from `SomeBaseClass` therefore has no effect.