[Bug c++/109871] New: error: call of overloaded ... ambiguous (std::vector vs designated initializers)

[Bug c++/109871] New: error: call of overloaded ... ambiguous (std::vector vs designated initializers)

[gnu.ojxq8 at dralias dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

            Bug ID: 109871
           Summary: error: call of overloaded ... ambiguous (std::vector
                    vs designated initializers)
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gnu.ojxq8 at dralias dot com
  Target Milestone: ---

When calling an overloaded function or constructor that takes a std::vector, as
well as a struct that allows designated initializers, the code is incorrectly
rejected by all versions of GCC, but accepted by Clang.

Example:

----------------
#include <vector>
struct S {};
struct Options {
    int opt{};
};
void A(std::vector<S>) {}
void A(Options) {}
int main() { A({.opt = 1}); }
----------------

Error:

----------------
<source>: In function 'int main()':
<source>:8:15: error: call of overloaded 'A(<brace-enclosed initializer list>)'
is ambiguous
    8 | int main() { A({.opt = 1}); }
      |              ~^~~~~~~~~~~~
<source>:6:6: note: candidate: 'void A(std::vector<S>)'
    6 | void A(std::vector<S>) {}
      |      ^
<source>:7:6: note: candidate: 'void A(Options)'
    7 | void A(Options) {}
      |      ^
Compiler returned: 1
----------------

There is PR 59389 and PR 86997, but they seem unrelated because they are not
about designated initializers.

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |accepts-invalid
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-05-16
     Ever confirmed|0                           |1
                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed, this seems to reduce to the accepts-invalid testcase:

#include <initializer_list>

struct vector {
  vector(std::initializer_list<int>); // #1
  vector(int); // #2
};

void f(vector);

int main() {
  f({.blah = 1}); // incorrectly accepted and resolves to #2
}

Not a regression.

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

Patrick Palka <ppalka at gcc dot gnu.org> changed:

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

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

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

https://gcc.gnu.org/g:d5e5007c4b534391c0a97be56f6024fde1a88682

commit r14-917-gd5e5007c4b534391c0a97be56f6024fde1a88682
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue May 16 12:39:16 2023 -0400

    c++: desig init in presence of list ctor [PR109871]

    add_list_candidates has logic to reject designated initialization of a
    non-aggregate type, but this is inadvertently being suppressed if the type
    has a list constructor due to the order of case analysis, which in the
    below testcase leads to us incorrectly treating the initializer list as if
    it's non-designated.  This patch fixes this by making us check for invalid
    designated initialization sooner.

            PR c++/109871

    gcc/cp/ChangeLog:

            * call.cc (add_list_candidates): Check for invalid designated
            initialization sooner and even for types that have a list
            constructor.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/desig27.C: New test.

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.2

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:efdcb731bbd6e20552fe878d54e59dc06af02334

commit r13-7357-gefdcb731bbd6e20552fe878d54e59dc06af02334
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue May 16 12:39:16 2023 -0400

    c++: desig init in presence of list ctor [PR109871]

    add_list_candidates has logic to reject designated initialization of a
    non-aggregate type, but this is inadvertently being suppressed if the type
    has a list constructor due to the order of case analysis, which in the
    below testcase leads to us incorrectly treating the initializer list as if
    it's non-designated.  This patch fixes this by making us check for invalid
    designated initialization sooner.

            PR c++/109871

    gcc/cp/ChangeLog:

            * call.cc (add_list_candidates): Check for invalid designated
            initialization sooner and even for types that have a list
            constructor.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp2a/desig27.C: New test.

    (cherry picked from commit d5e5007c4b534391c0a97be56f6024fde1a88682)

[Bug c++/109871] error: call of overloaded ... is ambiguous (std::vector vs designated initializers)

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109871

Patrick Palka <ppalka at gcc dot gnu.org> changed:

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

--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 13.2, thanks for the bug report.