This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 113d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-03-20


2614. Unspecified results for class member access

Section: 7.6.1.5  [expr.ref]     Status: C++23     Submitter: Andrey Erokhin     Date: 2021-10-27

[Accepted as a DR at the November, 2022 meeting.]

Subclause 7.6.1.5 [expr.ref] paragraph 6 specifies:

If E2 is declared to have type “reference to T”, then E1.E2 is an lvalue; the type of E1.E2 is T. Otherwise, ...

This does not specifiy which object or functiom the resulting lvalue designates. A similar problem exists with member enumerators:

If E2 is a member enumerator and the type of E2 is T, the expression E1.E2 is a prvalue. The type of E1.E2 is T.

Proposed resolution (approved by CWG 2022-09-23):

  1. Split and change in 7.6.1.5 [expr.ref] paragraph 6 as follows:

    If E2 is declared to have type “reference to T”, then E1.E2 is an lvalue; the of type of E1.E2 is T. If E2 is a static data member, E1.E2 designates the object or function to which the reference is bound, otherwise E1.E2 designates the object or function to which the corresponding reference member of E1 is bound.

    Otherwise, ...

  2. Change in 7.6.1.5 [expr.ref] bullet 6.5 as follows:

    If E2 is a member enumerator and the type of E2 is T, the expression E1.E2 is a prvalue. The of type of E1.E2 is T whose value is the value of the enumerator.