struct Base {
	virtual void foo() = 0;
};
 
struct Derived : Base {
	void foo() override{};
};
 
struct Thing {
	Thing(Base *b)
		: b(b) {}
	Base *b;
	void call_foo() const {
		b->foo(); //why do I not get an error? b is const and should not be able to call Base::foo
	}
};
 
int main() {
	Derived d;
	const Thing t(&d);
	t.call_foo();
 
	const Base *b = &d;
	//b->foo(); //this correctly says error: passing 'const Base' as 'this' argument discards qualifiers [-fpermissive]
}
 

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