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.

This check supports a fixit, however you'll need to set the env var CLAZY_ACCESSSPECIFIER_NON_QOBJECT=1. It's opt-in since it involves a bit of cpu overhead and is also responsible for bug #431186