[Bug c++/113760] [DR1693] gcc rejects valid empty-declaration in pedantic mode

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113760

--- Comment #18 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:0b3eac4b54a52bf206b88743d1e987badc97cff4

commit r15-522-g0b3eac4b54a52bf206b88743d1e987badc97cff4
Author: Marek Polacek <polacek@redhat.com>
Date:   Mon Feb 12 19:36:16 2024 -0500

    c++: DR 569, DR 1693: fun with semicolons [PR113760]

    Prompted by c++/113760, I started looking into a bogus "extra ;"
    warning in C++11.  It quickly turned out that if I want to fix
    this for good, the fix will not be so small.

    This patch touches on DR 569, an extra ; at namespace scope should
    be allowed since C++11:

      struct S {
      };
      ; // pedwarn in C++98

    It also touches on DR 1693, which allows superfluous semicolons in
    class definitions since C++11:

      struct S {
        int a;
        ; // pedwarn in C++98
      };

    Note that a single semicolon is valid after a member function definition:

      struct S {
        void foo () {}; // only warns with -Wextra-semi
      };

    There's a new function maybe_warn_extra_semi to handle all of the above
    in a single place.  So now they all get a fix-it hint.

    -Wextra-semi turns on all "extra ;" diagnostics.  Currently, options
    like -Wc++11-compat or -Wc++11-extensions are not considered.

            DR 1693
            PR c++/113760
            DR 569

    gcc/c-family/ChangeLog:

            * c.opt (Wextra-semi): Initialize to -1.

    gcc/cp/ChangeLog:

            * parser.cc (extra_semi_kind): New.
            (maybe_warn_extra_semi): New.
            (cp_parser_declaration): Call maybe_warn_extra_semi.
            (cp_parser_member_declaration): Likewise.

    gcc/ChangeLog:

            * doc/invoke.texi: Update -Wextra-semi documentation.

    gcc/testsuite/ChangeLog:

            * g++.dg/diagnostic/semicolon1.C: New test.
            * g++.dg/diagnostic/semicolon10.C: New test.
            * g++.dg/diagnostic/semicolon11.C: New test.
            * g++.dg/diagnostic/semicolon12.C: New test.
            * g++.dg/diagnostic/semicolon13.C: New test.
            * g++.dg/diagnostic/semicolon14.C: New test.
            * g++.dg/diagnostic/semicolon15.C: New test.
            * g++.dg/diagnostic/semicolon16.C: New test.
            * g++.dg/diagnostic/semicolon17.C: New test.
            * g++.dg/diagnostic/semicolon2.C: New test.
            * g++.dg/diagnostic/semicolon3.C: New test.
            * g++.dg/diagnostic/semicolon4.C: New test.
            * g++.dg/diagnostic/semicolon5.C: New test.
            * g++.dg/diagnostic/semicolon6.C: New test.
            * g++.dg/diagnostic/semicolon7.C: New test.
            * g++.dg/diagnostic/semicolon8.C: New test.
            * g++.dg/diagnostic/semicolon9.C: New test.