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From: "avi at scylladb dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/106847] New: deprecated class data member makes the class
 generate diagnostics even when the member is not used
Date: Tue, 06 Sep 2022 10:33:33 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 13.0
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X-Bugzilla-Severity: normal
X-Bugzilla-Who: avi at scylladb dot com
X-Bugzilla-Status: UNCONFIRMED
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X-Bugzilla-Priority: P3
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106847

            Bug ID: 106847
           Summary: deprecated class data member makes the class generate
                    diagnostics even when the member is not used
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: avi at scylladb dot com
  Target Milestone: ---

A class with a deprecated member:

    struct foo {
        [[deprecated]] bool x;
    };

Cannot be used without lots of noise from the compiler:

    foo make_a_foo() {
        foo f;
        return f;
    }

<source>: In function 'foo make_a_foo()':
<source>:10:12: warning: 'f' is used uninitialized [-Wuninitialized]
   10 |     return f;
      |            ^
<source>:9:9: note: 'f' declared here
    9 |     foo f;
      |         ^
Compiler returned: 0


Although I didn't touch x, the compiler thinks I did. IMO synthesized
constructors (and assignment operators) should suppress the warning and only
explicit access by the user should trigger the warning.=