README-copyable-polymorphic.md

copyable-polymorphic

Finds polymorphic classes that are copyable. Classes with virtual methods are usually handled by pointer, as passing then by value would allow up-casting to the base-class and slicing off the vtable. Example:

struct Base {
    virtual int getNumber() const { return 41; }
};

struct Derived : public Base {
    int getNumber() const override { return 42; }
};

void printNumber(Base b)
{
    qDebug() << b.getNumber(); // Always prints 41!
}

(...)
Derived d;
printNumber(d);

To fix these warnings use Q_DISABLE_COPY or delete the copy-ctor yourself.