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


2353. Potential results of a member access expression for a static data member

Section: 6.3  [basic.def.odr]     Status: CD5     Submitter: Richard Smith     Date: 2017-08-18

[Accepted as a DR at the February, 2019 meeting.]

According to 6.3 [basic.def.odr] bullet 2.3, the potential results of a member access expression are simply the object expression. This rule incorrectly handles an example like:

  struct X {
    static const int n = 0;
  };
  X x = {};

  int b = x.n;

Because X::n is not one of the potential results, the expression x.n odr-uses X::n, requiring it to be defined.

Notes from the April, 2018 teleconference:

CWG agreed with the suggested direction to make the member a potential result in cases like the example.

Proposed resolution (February, 2019):

Change 6.3 [basic.def.odr] paragraph 2 as follows:

An expression is potentially evaluated unless it is an unevaluated operand (7.2 [expr.prop]) or a subexpression thereof. The set of potential results of an expression e is defined as follows: