[Bug c++/99318] New: [10/11 Regression] -Wdeprecated-declarations where non-should be?

[Bug c++/99318] New: [10/11 Regression] -Wdeprecated-declarations where non-should be?

[gcc-bugs at marehr dot dialup.fu-berlin.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

            Bug ID: 99318
           Summary: [10/11 Regression] -Wdeprecated-declarations where
                    non-should be?
           Product: gcc
           Version: 10.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc-bugs at marehr dot dialup.fu-berlin.de
  Target Milestone: ---

Hello gcc-team,

since gcc 10 the following code throws a deprecation warning, even though it
doesn't use any deprecated code.

```c++
template <typename derived_type>
class alphabet_base
{
    [[deprecated("message")]] unsigned char_to_rank_table(char const chr)
    {
        using index_t = unsigned;
        return derived_type::char_to_rank[static_cast<index_t>(chr)];
    }
};

```

gives the following warning:

```
<source>: In member function 'unsigned int
alphabet_base<derived_type>::char_to_rank_table(char)':
<source>:7:55: warning: 'unsigned int
alphabet_base<derived_type>::char_to_rank_table(char)' is deprecated: message
[-Wdeprecated-declarations]
    7 |         return derived_type::char_to_rank[static_cast<index_t>(chr)];
      |                                                       ^~~~~~~
<source>:4:40: note: declared here
    4 |     [[deprecated("message")]] unsigned char_to_rank_table(char const
chr)
      |                                        ^~~~~~~~~~~~~~~~~~
Compiler returned: 0
```

See https://godbolt.org/z/4cWzMr

Thank you!

[Bug c++/99318] [10/11 Regression] -Wdeprecated-declarations where non-should be?

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.3
           Keywords|                            |diagnostic, rejects-valid

[Bug c++/99318] [10/11 Regression] -Wdeprecated-declarations where non-should be?

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |mpolacek at gcc dot gnu.org
   Last reconfirmed|                            |2021-03-09
           Priority|P3                          |P2
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r10-2790-g5857042a2b3dd635fc6cae214abd60d3a8336060

[Bug c++/99318] [10/11 Regression] -Wdeprecated-declarations where non-should be?

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

[Bug c++/99318] [10/11 Regression] -Wdeprecated-declarations where non-should be?

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:831f9f768eb1fbf9a31d9a89591188b1487b6376

commit r11-7789-g831f9f768eb1fbf9a31d9a89591188b1487b6376
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Mar 9 19:23:48 2021 -0500

    c++: Fix bogus warning in deprecated namespace [PR99318]

    In GCC 10, I introduced cp_warn_deprecated_use_scopes so that we can
    handle attribute deprecated on a namespace declaration.  This
    function walks the decl's contexts so that we warn for code like

      namespace [[deprecated]] N { struct S { }; }
      N::S s;

    We call cp_warn_deprecated_use_scopes when we encounter a TYPE_DECL.
    But in the following testcase we have a TYPE_DECL whose context is
    a deprecated function; that itself is not a reason to warn.  This
    patch limits for which entities we call cp_warn_deprecated_use;
    essentially it's what can follow ::.

    I noticed that we didn't test that

      struct [[deprecated]] S { static void fn(); };
      S::fn();

    produces the expected warning, so I've added gen-attrs-73.C.

    gcc/cp/ChangeLog:

            PR c++/99318
            * decl2.c (cp_warn_deprecated_use_scopes): Only call
            cp_warn_deprecated_use when decl is a namespace, class, or enum.

    gcc/testsuite/ChangeLog:

            PR c++/99318
            * g++.dg/cpp0x/attributes-namespace6.C: New test.
            * g++.dg/cpp0x/gen-attrs-73.C: New test.

[Bug c++/99318] [10 Regression] -Wdeprecated-declarations where non-should be?

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[10/11 Regression]          |[10 Regression]
                   |-Wdeprecated-declarations   |-Wdeprecated-declarations
                   |where non-should be?        |where non-should be?

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug c++/99318] [10 Regression] -Wdeprecated-declarations where non-should be?

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:9879b82c77b0c65e39607a0a2d0891ebc75c5995

commit r10-9554-g9879b82c77b0c65e39607a0a2d0891ebc75c5995
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Mar 9 19:23:48 2021 -0500

    c++: Fix bogus warning in deprecated namespace [PR99318]

    In GCC 10, I introduced cp_warn_deprecated_use_scopes so that we can
    handle attribute deprecated on a namespace declaration.  This
    function walks the decl's contexts so that we warn for code like

      namespace [[deprecated]] N { struct S { }; }
      N::S s;

    We call cp_warn_deprecated_use_scopes when we encounter a TYPE_DECL.
    But in the following testcase we have a TYPE_DECL whose context is
    a deprecated function; that itself is not a reason to warn.  This
    patch limits for which entities we call cp_warn_deprecated_use;
    essentially it's what can follow ::.

    I noticed that we didn't test that

      struct [[deprecated]] S { static void fn(); };
      S::fn();

    produces the expected warning, so I've added gen-attrs-73.C.

    gcc/cp/ChangeLog:

            PR c++/99318
            * decl2.c (cp_warn_deprecated_use_scopes): Only call
            cp_warn_deprecated_use when decl is a namespace, class, or enum.

    gcc/testsuite/ChangeLog:

            PR c++/99318
            * g++.dg/cpp0x/attributes-namespace6.C: New test.
            * g++.dg/cpp0x/gen-attrs-73.C: New test.

    (cherry picked from commit 831f9f768eb1fbf9a31d9a89591188b1487b6376)

[Bug c++/99318] [10 Regression] -Wdeprecated-declarations where non-should be?

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
      Known to fail|                            |10.2.0

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.

[Bug c++/99318] [10 Regression] -Wdeprecated-declarations where non-should be?

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99318

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |shyouhei@ruby-lang.org

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 95302 has been marked as a duplicate of this bug. ***