Are fully qualified class names permitted for ctor declarations?

[winkerbean]

Given the following:

class A
{
class B
{
A::B( A::B const & );
};
};

Is the above ctor declaration valid C++? ISO C++ 2003, 12.1,
paragraph 1 states:

"Constructors do not have names. A special declarator syntax using an
optional sequence of function-specifiers (7.1.2) followed by the
constructor’s class name followed by a parameter list is used to
declare or define the constructor. In such a declaration, optional
parentheses around the constructor class name are ignored."

However, as best I can tell, the ISO standard does not specify if the
class name may or may not be a fully qualified class name.

Thanks in advance.

 

[Ian Collins]

Given the following:

class A
{
class B
{
A::B( A::B const & );
};
};

Is the above ctor declaration valid C++?

No.

 

[winkerbean]

No.

Why?