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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/109470] unexpected const & behavior
Date: Tue, 11 Apr 2023 10:37:06 +0000	[thread overview]
Message-ID: <bug-109470-4-W7YAJhSW89@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109470-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109470

--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
No, "full-expression" is a formal term defined very precisely in the C++
standard. There is no opportunity for GCC to review that without failing to
conform to the C++ standard. Changing when temporary objects are destroyed
would be a massive breaking change to the C++ language that would break
assumptions made by correct code.

Just because you don't get a warning with other compilers, doesn't mean your
code is correct. The code accesses an object outside its lifetime, and so has
undefined behaviour. That is true with all compilers.

Clang gives a runtime error with -fsanitize=address e.g.
https://godbolt.org/z/dhcEhvzze

That's because the program has undefined behaviour. This is not just GCC's
interpretation of the C++ standard, it's a fact.

      parent reply	other threads:[~2023-04-11 10:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-11  7:43 [Bug c++/109470] New: " johannes.kellner at wandelbots dot com
2023-04-11  8:25 ` [Bug c++/109470] " xry111 at gcc dot gnu.org
2023-04-11  8:36 ` xry111 at gcc dot gnu.org
2023-04-11  9:48 ` johannes.kellner at wandelbots dot com
2023-04-11  9:52 ` pinskia at gcc dot gnu.org
2023-04-11  9:56 ` redi at gcc dot gnu.org
2023-04-11 10:23 ` johannes.kellner at wandelbots dot com
2023-04-11 10:36 ` jakub at gcc dot gnu.org
2023-04-11 10:37 ` redi at gcc dot gnu.org [this message]

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