[Bug c++/99969] New: g++ incorrectly thinks a private destructor is available

[Bug c++/99969] New: g++ incorrectly thinks a private destructor is available

[Steffen.Kiess at ipvs dot uni-stuttgart.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99969

            Bug ID: 99969
           Summary: g++ incorrectly thinks a private destructor is
                    available
           Product: gcc
           Version: 10.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Steffen.Kiess at ipvs dot uni-stuttgart.de
  Target Milestone: ---

Created attachment 50527
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50527&action=edit
Test case

The attached test case will fail to compile (because g++ chooses thinks the
first overload should match, even though the destructor of C is private and
"delete std::declval<T *>()" therefore should note compile). This is somehow
related to the fact the "decltype(test((C *)nullptr))" is referred to from a
template context before it is used in main() (if the struct S is removed or
moved below the main() function the code will compile).

The problem occurs with gcc 10.2.0 (but also with older versions, at least back
to 4.9).

[Bug c++/99969] g++ incorrectly thinks a private destructor is available

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99969

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This seems fixed since GCC 11.

[Bug c++/99969] g++ incorrectly thinks a private destructor is available

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99969

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

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

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed by r11-1350

    c++: Improve access checking inside templates [PR41437]

    This patch generalizes our existing functionality for deferring access
    checking of typedefs when parsing a function or class template to now
    defer all kinds of access checks until template instantiation time,
    including member function and member object accesses.

    Since all access checks eventually go through enforce_access, the main
    component of this patch is new handling inside enforce_access to defer
    the current access check if we're inside a template.  The bulk of the
    rest of the patch consists of removing now-unneeded code pertaining to
    suppressing access checks inside templates or pertaining to
    typedef-specific access handling.  Renamings and other changes with no
    functional impact have been split off into the followup patch.

    gcc/cp/ChangeLog:

            PR c++/41437
            PR c++/47346
            * call.c (enforce_access): Move to semantics.c.
            * cp-tree.h (enforce_access): Delete.
            (get_types_needing_access_check): Delete.
            (add_typedef_to_current_template_for_access_check): Delete.
            * decl.c (make_typename_type): Adjust accordingly.  Use
            check_accessibility_of_qualified_id instead of directly using
            perform_or_defer_access_check.
            * parser.c (cp_parser_template_declaration_after_parameters):
            Don't push a dk_no_check access state when parsing a template.
            * pt.c (get_types_needing_access_check): Delete.
            (append_type_to_template_for_access_check_1): Delete.
            (perform_typedefs_access_check): Adjust.  If type_decl is a
            FIELD_DECL, also check its DECL_CONTEXT for dependence. Use
            tsubst_copy instead of tsubst to substitute into type_decl so
            that we substitute into the DECL_CONTEXT of a FIELD_DECL.
            (append_type_to_template_for_access_check): Delete.
            * search.c (accessible_p): Remove the processing_template_decl
            early exit.
            * semantics.c (enforce_access): Moved from call.c.  If we're
            parsing a template and the access check failed, add the check to
            TI_TYPEDEFS_NEEDING_ACCESS_CHECKING.
            (perform_or_defer_access_check): Adjust comment.
            (add_typedef_to_current_template_for_access_check): Delete.
            (check_accessibility_of_qualified_id):  Adjust accordingly.
            Exit early if the scope is dependent.

    gcc/testsuite/ChangeLog:

            PR c++/41437
            PR c++/47346
            * g++.dg/cpp2a/concepts-using2.C: Adjust.
            * g++.dg/lto/20081219_1.C: Adjust.
            * g++.dg/lto/20091002-1_0.C: Adjust.
            * g++.dg/lto/pr65475c_0.C: Adjust.
            * g++.dg/opt/dump1.C: Adjust.
            * g++.dg/other/pr53574.C: Adjust.
            * g++.dg/template/access30.C: New test.
            * g++.dg/template/access31.C: New test.
            * g++.dg/wrappers/wrapper-around-type-pack-expansion.C: Adjust.

    libstdc++-v3/ChangeLog:

            PR libstdc++/94003
            * testsuite/20_util/is_constructible/94003.cc: New test.

[Bug c++/99969] g++ incorrectly thinks a private destructor is available

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99969

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0