"calls constructor, not type" in g ++ 4.4.7

Question

I have the following simple C ++ code:

#include <cstdio>

class A
{
public:
    A(int y) : x(y) {}
    A& operator=(const A& rhs);
    int x;
};

A::A& A::operator=(const A& rhs) { this->x = rhs.x; return *this; }

int main(int, char**)
{
    A a1(5);
    A a2(4);

    printf("a2.x == %d\n", a2.x);

    a2 = a1;

    printf("a2.x == %d\n", a2.x);

    return 0;
}

Line 11, where the definition of the function A operator=()is equal, garbled ... or at least I think so. As expected, g ++ 4.7.4, as well as every new version of GCC I tried, produces the following error:

main.cpp:11:1: error: ‘A::A’ names the constructor, not the type

Oddly enough, g ++ 4.4.7 will compile this program without warnings and even prints 4 and 5, as you would expect if line 11 was spelled correctly (i.e. using A&instead A::A&).

- , g++ 4.4.7? ( , )? , , ​​ operator=().

Answer 1

g++ . 4.5.0, 4.4.7 .

:

cc1plus . , , A:: A ( )

struct A { };

int main()
{
    A::A a;       // should be an ERROR
}

, A::A , . , , 4.5.0.

Answer 2

dasblinkenlight - ++ 03 [class.qual]:

C, -, C, inced-class-name of C ( 9), C. declarator , . [:

struct A { A(); };
struct B: public A { B(); };

A::A() { }
B::B() { }

B::A ba; // object of type A
A::A a;  // error, A::A is not a type name

-end ]