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That's not even particularly good advice, which just goes to show how subtle the pitfalls are. The rule really should be "If it is at all possible to delete ins

That's not even particularly good advice, which just goes to show how subtle the pitfalls are. The rule really should be "If it is at all possible to delete instances from a pointer to the base class, then you need a virtual destructor". The overhead of adding a virtual destructor to a base class with no other virtual functions is far from negligible in many cases, so the distinction is meaningful (though modern guidance tends discourage non-polymorphic inheritance in the first place anyways). The same thing goes for the good-old "Do not use raw pointers." The rule is actually: "Do not use raw pointers with implicit ownership semantics attached to them."

nyanpasu64 4y ago
In retrospect I wish C++ used fat pointers rather than inheritance for virtual dispatch, like Rust but where interfaces/traits can have fields (Rust traits don't have fields and are less powerful than C++ base classes). This prevents accidentally overriding a base class method (eg. QWidget) by declaring a subclass method of the same name, eliminates the need to add a vtable pointer to object instances which you never cast to an interface pointer, and eliminates the need to juggle pointer offsets when performing multiple inheritance method calls, which can cause UB when performing C-style pointer casts and makes decompiling the code a nightmare (possibly fields in traits will add this requirement again, I'm not sure).