CWG Issue 139 (original) (raw)

This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 117a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-04-13

139. Error in friend lookup example

Section: 6.5.3 [basic.lookup.unqual]Status: CD1Submitter: Mike MillerDate: 14 Jul 1999

[Moved to DR at 10/01 meeting.]

The example in 6.5.3 [basic.lookup.unqual] paragraph 3 is incorrect:

typedef int f;
struct A {
    friend void f(A &);
    operator int();
    void g(A a) {
        f(a);
    }
};

Regardless of the resolution of other issues concerning the lookup of names in friend declarations, this example is ill-formed (the function and the typedef cannot exist in the same scope).

One possible repair of the example would be to make fa class with a constructor taking either A or intas its parameter.

(See also issues95,136,138,143,165, and166.)

Proposed resolution (04/01):

1. Change the example in 6.5.3 [basic.lookup.unqual] paragraph 3 to read:
   typedef int f;
   namespace N {
   struct A {
   friend int f(A &);
   operator int();
   void g(A a) {
   int i = f(a);
   // f is the typedef, not the friend function:
   // equivalent to int(a)
   }
   };
   }
2. Delete the sentence immediately following the example:

   The expression f(a) is a _cast-expression_equivalent to int(a).