Title
Should the enclosing class be an "associated class" too?
Status
tc1
Section
6.4.2 [basic.lookup.argdep]
Submitter
John Spicer

Created on 1999-02-02.00:00:00 last changed 208 months ago

Messages

Date: 1999-10-15.00:00:00

Proposed Resolution (10/99): Change the two referenced bullets to read:

  • If T is a class type (including unions), its associated classes are: the class itself; the class of which it is a member, if any; and its direct and indirect base classes. Its associated namespaces are the namespaces in which its associated classes are defined.
  • If T is an enumeration type, its associated namespace is the namespace in which it is defined. If it is class member, its associated class is the member's class; else it has no associated class.
(This proposal also addresses Core issue 91.)
Date: 2004-09-10.00:00:00

Section 6.4.2 [basic.lookup.argdep] includes the following:

  • If T is a class type, its associated classes are the class itself and its direct and indirect base classes. Its associated namespaces are the namespaces in which its associated classes are defined.
  • If T is a union or enumeration type, its associated namespace is the namespace in which it is defined. If it is a class member, its associated class is the member's class; else it has no associated class.
Note that for a union, the enclosing class is an "associated class", but for a class type the enclosing class is not an "associated class". This results in some surprising behavior, as shown in the example below.
    struct A {
        union U {};
        friend void f(U);
    };

    struct B {
        struct S {};
        friend void f(S);
    };

    int main() { 
        A::U    u; 
        f(u);        // okay: A is an associated class
        B::S    s;
        f(s);        // error: no matching f(), B is not an associated class
    }

Certainly the enclosing class should also be an associated class for nested class types, shouldn't it?
History
Date User Action Args
2003-04-25 00:00:00adminsetstatus: dr -> tc1
2000-02-23 00:00:00adminsetmessages: + msg296
2000-02-23 00:00:00adminsetstatus: review -> dr
1999-02-02 00:00:00admincreate