public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "jewillco at osl dot iu.edu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/54379] New: Suggestion for type attribute similar to warn_unused_result
Date: Sun, 26 Aug 2012 23:13:00 -0000	[thread overview]
Message-ID: <bug-54379-4@http.gcc.gnu.org/bugzilla/> (raw)

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54379

             Bug #: 54379
           Summary: Suggestion for type attribute similar to
                    warn_unused_result
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jewillco@osl.iu.edu


I think it would be useful to extend GCC with an attribute similar to
`warn_unused_result` but applying to a user-defined type rather than just a
single function.  The effect would be that all expressions (variable
references, function calls, etc.) that return some object of that type would
warn if their results were unused.  The intended use case is for C++ patterns
such as expression templates in which purely-functional code builds up an
expression tree which does not make sense to discard; in some cases, operator=
would just add to the expression tree as well, leading to a source of bugs. 
This would probably require the kind of cast-to-void override mechanism that PR
25509 is about, since these annotations would strictly be recommendations.


             reply	other threads:[~2012-08-26 23:13 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-26 23:13 jewillco at osl dot iu.edu [this message]
2021-05-31 21:16 ` [Bug c++/54379] " redi at gcc dot gnu.org
2021-09-17  6:41 ` pinskia at gcc dot gnu.org

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=bug-54379-4@http.gcc.gnu.org/bugzilla/ \
    --to=gcc-bugzilla@gcc.gnu.org \
    --cc=gcc-bugs@gcc.gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).