[Bug c++/94231] New: Invalid move constructor defaulted outside of class as deleted is accepted

[Bug c++/94231] New: Invalid move constructor defaulted outside of class as deleted is accepted

[herring at lanl dot gov]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94231

            Bug ID: 94231
           Summary: Invalid move constructor defaulted outside of class as
                    deleted is accepted
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: herring at lanl dot gov
  Target Milestone: ---

GCC incorrectly accepts the following:

  struct F {F(F&&)=delete;};

  template<int=0>
  struct M {
    F f;
    M();
    M(const M&);
    M(M&&);
  };

  template<int I>
  M<I>::M(M&&)=default;

  M<> f() {
    M<> m;
    return m;
  }

The returned value is implicitly moved-from (although adding static_cast<M<>&&>
makes no difference), which should discover that M's move constructor is
invalid because it is defaulted after its first declaration and defined as
deleted, but simply falls back to the copy constructor instead.

If M is not a template, GCC correctly rejects, although the error messages are
a bit confused.

[Bug c++/94231] Invalid move constructor defaulted outside of class as deleted is accepted

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94231

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mpolacek at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2020-04-18
     Ever confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed, thanks for the report.  Not a regression.

[Bug c++/94231] Invalid move constructor defaulted outside of class as deleted is accepted

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94231

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

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

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Seems to have been fixed by the very recent r14-8759.  I'll add the test.

[Bug c++/94231] Invalid move constructor defaulted outside of class as deleted is accepted

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94231

--- Comment #3 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:1befe47f64bf0b964be90730e2cbef550cb6d2b7

commit r14-8830-g1befe47f64bf0b964be90730e2cbef550cb6d2b7
Author: Marek Polacek <polacek@redhat.com>
Date:   Tue Feb 6 11:44:44 2024 -0500

    c++: add fixed test [PR94231]

    I was suprised to find out that r14-8759 fixed this accepts-invalid.

    clang version 17.0.6 rejects the test as well; clang version 19.0.0git
    crashes for which I opened
    <https://github.com/llvm/llvm-project/issues/80869>.

            PR c++/94231

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/deleted17.C: New test.

[Bug c++/94231] Invalid move constructor defaulted outside of class as deleted is accepted

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94231

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Hopefully fixed.