[Bug c++/71093] use of pseudo-destructor accepted in constant expression

[Bug c++/71093] use of pseudo-destructor accepted in constant expression

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71093

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2017-02-16 00:00:00         |2021-8-11

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note p->~T() is valid for C++20 but not exactly.

[Bug c++/71093] use of pseudo-destructor accepted in constant expression

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71093

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:90bc2d09b5bfcc913f79543c3b65202e7246e162

commit r14-6508-g90bc2d09b5bfcc913f79543c3b65202e7246e162
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Fri Nov 3 12:18:29 2023 +1100

    c++: End lifetime of objects in constexpr after destructor call [PR71093]

    This patch adds checks for using objects after they've been manually
    destroyed via explicit destructor call. Currently this is only
    implemented for 'top-level' objects; FIELD_DECLs and individual elements
    of arrays will need a lot more work to track correctly and are left for
    a future patch.

    The other limitation is that destruction of parameter objects is checked
    too 'early', happening at the end of the function call rather than the
    end of the owning full-expression as they should be for consistency;
    see cpp2a/constexpr-lifetime2.C. This is because I wasn't able to find a
    good way to link the constructed parameter declarations with the
    variable declarations that are actually destroyed later on to propagate
    their lifetime status, so I'm leaving this for a later patch.

            PR c++/71093

    gcc/cp/ChangeLog:

            * constexpr.cc (constexpr_global_ctx::get_value_ptr): Don't
            return NULL_TREE for objects we're initializing.
            (constexpr_global_ctx::destroy_value): Rename from remove_value.
            Only mark real variables as outside lifetime.
            (constexpr_global_ctx::clear_value): New function.
            (destroy_value_checked): New function.
            (cxx_eval_call_expression): Defer complaining about non-constant
            arg0 for operator delete. Use remove_value_safe.
            (cxx_fold_indirect_ref_1): Handle conversion to 'as base' type.
            (outside_lifetime_error): Include name of object we're
            accessing.
            (cxx_eval_store_expression): Handle clobbers. Improve error
            messages.
            (cxx_eval_constant_expression): Use remove_value_safe. Clear
            bind variables before entering body.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp1y/constexpr-lifetime1.C: Improve error message.
            * g++.dg/cpp1y/constexpr-lifetime2.C: Likewise.
            * g++.dg/cpp1y/constexpr-lifetime3.C: Likewise.
            * g++.dg/cpp1y/constexpr-lifetime4.C: Likewise.
            * g++.dg/cpp2a/bitfield2.C: Likewise.
            * g++.dg/cpp2a/constexpr-new3.C: Likewise. New check.
            * g++.dg/cpp1y/constexpr-lifetime7.C: New test.
            * g++.dg/cpp2a/constexpr-lifetime1.C: New test.
            * g++.dg/cpp2a/constexpr-lifetime2.C: New test.

    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>

[Bug c++/71093] use of pseudo-destructor accepted in constant expression

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71093

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=113031

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This causes new ICEs for the libstdc++ test suite, see PR 113031