Body for pure virtual function in C++17?

Question

I tried to write an pure virtual function in Base class, and i give it an body near the definition as it shown in the code bellow, as I know i should get an compile error, But everything worked fine. Is it something new that come with C++17 ? (I used visual studio 2017)

class Base {
public:
virtual void virtual_func() { std::cout << "This a virtual function from BASE" << std::endl; };
virtual void pure_func() = 0 { std::cout << "This a PURE virtual function from BASE" << std::endl; };
};

Thanks

Answer 1

The pure virtual cannot be used together with a definition. This was true in C++11, and in C++14:

10.4/2:...
[ Note: A function declaration cannot provide both a pure-specifier and a definition — end note ] [ Example:

struct C {
virtual void f() = 0 { }; // ill-formed
};

The same statement (under section 13.4/2 this time) is still true for C++17 (N4659).

So if your compiler accept this code, it's certainly a bug (gcc 7.1 doesesn't)