This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 110b. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2023-01-15


10. Can a nested class access its own class name as a qualified name if it is a private member of the enclosing class?

Section: 11.8.8  [class.access.nest]     Status: CD1     Submitter: Josee Lajoie     Date: unknown

[Moved to DR at 4/01 meeting.]

Paragraph 1 says: "The members of a nested class have no special access to members of an enclosing class..."

This prevents a member of a nested class from being defined outside of its class definition. i.e. Should the following be well-formed?

    class D {
        class E {
            static E* m;
        };
    };

    D::E* D::E::m = 1; // ill-formed
This is because the nested class does not have access to the member E in D. 11.8 [class.access] paragraph 5 says that access to D::E is checked with member access to class E, but unfortunately that doesn't give access to D::E. 11.8 [class.access] paragraph 6 covers the access for D::E::m, but it doesn't affect the D::E access. Are there any implementations that are standard compliant that support this?

Here is another example:

    class C {
        class B
        {
            C::B *t; //2 error, C::B is inaccessible
        };
    };
This causes trouble for member functions declared outside of the class member list. For example:
    class C {
        class B
        {
            B& operator= (const B&);
        };
    };

    C::B& C::B::operator= (const B&) { } //3
If the return type (i.e. C::B) is access checked in the scope of class B (as implied by 11.8 [class.access] paragraph 5) as a qualified name, then the return type is an error just like referring to C::B in the member list of class B above (i.e. //2) is ill-formed.

Proposed resolution (04/01):

The resolution for this issue is incorporated into the resolution for issue 45.