Meaning of phrase “constructors do not have names”

问题:

While trying to understand the phrase "constructors do not have names" in the C++ Standard, it seems like I found an error in clang. Could someone confirm this?

VS2015 and gcc rejects this code, and I think they it are is correct. At least, this is the impression I get from §12.1[class.ctor]/2 in N4140:

#include <iostream>
class A {
public:
    A() { std::cout << "A()" << '\n'; }
};

int main()
{
  A::A();
}

§12.1[class.ctor]/2 in N4140:

A constructor is used to initialize objects of its class type. Because constructors do not have names, they are never found during name lookup; ...

With the expression A::A(); above, clang finds the constructor by name lookup, when it should find the type name A instead. See live example.

回答1:

Your intuition is correct. This is a known Clang bug 13403 with status NEW.

回答2:

I agree that this should not compile.

It's actually more bizzare than you thought. Try this:

#include <iostream>
#include <string>

class A {
public:
    A() {
        std::cout << "A() " << this << '\n';
    }

    void foo() {
        std::cout << _message << std::endl;
    }

    std::string _message = "hello";
};

int main()
{
    A::A().foo();
}

example output:

A() 0x7fff5cd105f8
hello

It looks to me as if an un-named A is being implicitly created.