This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-11-11

6. Should the optimization that allows a class object to alias another object also allow the case of a parameter in an inline function to alias its argument?

Section: 11.9.6  [class.copy.elision]     Status: NAD     Submitter: unknown     Date: unknown

[Picked up by evolution group at October 2002 meeting.]

(See also paper J16/99-0005 = WG21 N1182.)

At the London meeting, 11.4.5.3 [class.copy.ctor] paragraph 31 was changed to limit the optimization described to only the following cases:

One other case was deemed desirable as well: However, there are cases when this aliasing was deemed undesirable and, at the London meeting, the committee was not able to clearly delimit which cases should be allowed and which ones should be prohibited.

Can we find an appropriate description for the desired cases?

Rationale (04/99): The absence of this optimization does not constitute a defect in the Standard, although the proposed resolution in the paper should be considered when the Standard is revised.

Note (March, 2008):

The Evolution Working Group has accepted the intent of this issue and referred it to CWG for action (not for C++0x). See paper J16/07-0033 = WG21 N2173.

Notes from the June, 2008 meeting:

The CWG decided to take no action on this issue until an interested party produces a paper with analysis and a proposal.

Rationale (2023-05-12):

This is an extension that needs a paper targeted at EWG.