This suggestion should be decided by SG10 rather than being
handled as a core language issue, so I'm forwarding it to the
SG10 chair for consideration. Thanks.
-------- Forwarded Message --------
Subject: New issue: auto(x) should have a feature-testing macro
Date: Tue, 14 Dec 2021 02:48:12 +0000
From: Zhihao Yuan <
zy@miator.net>
Reply-To: Zhihao Yuan <
zy@miator.net>
To: William M. \(Mike\) Miller <
wmm@edg.com>
CC: 'Arthur O'Dwyer' <
arthur.j.odwyer@gmail.com>
It's hard to detect whether it is legal to
do auto(expr) after adopting P0849R8;
A feature testing macro would help.
There was no __cpp_auto (unlike
__cpp_decltype_auto), but the direction
of evolving auto(x) is probably not
necessarily tied to `auto` in a
declaration.
Proposed resolution:
This wording is relative to N4901.
Add an entry to [tab:cpp.predefined.ft]
Table 21: Feature-test macros
| Macro name | Value |
| -------- | ------- || <ins>__cpp_auto_cast</ins> | 202110L |
--
Zhihao Yuan, ID lichray
The best way to predict the future is to invent it.
_______________________________________________