Warning #2026 when compiling with icpc and -Wnon-virtual-dtor

[Kempke__Nils-Christi]

Hi,

I was trying to compile some code of mine which, in g++ (with the --Wnon-virtual-dtor Flag) compiled just fine.

When I tried to compile the same code with Intel's icpc (actually this one icpc (ICC) 19.1.2.254 20200623) I got a warning which I was now able to track down - I'm wondering whether I'm somehow at fault or whether that warning is actually not correct in my case.

I wrote a somewhat minimal example of my class hierarchy:

template<typename T>
class B {
        public:
                B() = default;
                virtual ~B() = default;
};

template<typename T>
class C : public B<T> {
        public:
                C() = default;
                ~C() override = default;

                virtual int foo() { return 0; };
};

template<typename T>
class D : public C<T> {
        public:
                D() = default;
                ~D() override = default;
                int foo() override { return 1; };
};


int main() {
        return 0;
}

When compiling this with 

icpc -Wnon-virtual-dtor foo.cpp

I get the following warning:

foo.cpp(15): warning #2026: Effective C++ Item 14 Make sure base classes C have virtual destructors
};
^

One can get rid of the warning by explicitly stating that the destructor in C is virtual, so having

virtual ~C() override = default;

Note, that also getting rid of the template lets the code compile without any warning.

For last - also getting rid of the foo member function will let the code compile without warning.

So yeah - my question is: is this a "bug" in icpc or did I do something wrong?

Thanks in advance,
Nils

[VidyalathaB_Intel]

Hi Nils,

Thanks for sharing the reproducer.

we tried it from our end and reproduced the same.

We are looking into this issue internally. We will get back to you soon.

Regards,

Vidya.

[Viet_H_Intel · Accepted solution]

Compiler emits this spurious warning 2026. But since there is a workaround, we most likely are not going to fix it.

Thanks,

[Viet_H_Intel]

Hi Nils,

Can we close this thread?

Thanks,

[Kempke__Nils-Christi]

Yes, sorry - I thought accepting a solution would somehow close it anyway, my bad.

[Viet_H_Intel]

Thanks.

This issue has been resolved and we will no longer respond to this thread. If you require additional assistance from Intel, please start a new thread. Any further interaction in this thread will be considered community only.