[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[john.lindgren at aol dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #1 from John Lindgren <john.lindgren at aol dot com> ---
Created attachment 33860
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33860&action=edit
Test case 2

[Bug c++/63707] New: Brace initialization of array sometimes fails if no copy constructor

[john.lindgren at aol dot com]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="UTF-8", Size: 3796 bytes --]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

            Bug ID: 63707
           Summary: Brace initialization of array sometimes fails if no
                    copy constructor
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: john.lindgren at aol dot com

Created attachment 33859
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33859&action=edit
Test case 1

Brace-initializing an array of a class without a public copy constructor gives
an error in some cases but succeeds in others.  After discussing the problem
here [1], I believe this is bug in GCC.

Attached are three test cases:
test1-fails.cc: Initialization of member array of non-literal type (error)
test2-works.cc: Initialization of member array of literal type (compiles)
test3-works.cc: Initialization of static array of non-literal type (compiles)
test4-works.cc: Initialization of single member of non-literal type (compiles)

The error given is:
$ g++ -Wall -Wextra -std=c++11 -c test1-fails.cc 
test1-fails.cc: In constructor ‘Parent::Parent()’:
test1-fails.cc:13:35: error: use of deleted function ‘Child::Child(const
Child&)’
     Parent () : children {{5}, {7}} {}
                                   ^
test1-fails.cc:7:5: note: declared here
     Child (const Child &) = delete;
     ^

$ g++ --version
g++ (GCC) 4.9.1 20140903 (prerelease)

By way of comparison, Clang 3.5.0 compiles all three test cases without errors.

[1]
http://stackoverflow.com/questions/26685551/how-to-initialize-array-of-classes-with-deleted-copy-constructor-c11
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From: "john.lindgren at aol dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc707

--- Comment #3 from John Lindgren <john.lindgren at aol dot com> ---
Created attachment 33862
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id3862&actioníit
Test case 4

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[john.lindgren at aol dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #2 from John Lindgren <john.lindgren at aol dot com> ---
Created attachment 33861
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33861&action=edit
Test case 3

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[john.lindgren at aol dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

John Lindgren <john.lindgren at aol dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #33860|0                           |1
        is obsolete|                            |

--- Comment #4 from John Lindgren <john.lindgren at aol dot com> ---
Created attachment 33863
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33863&action=edit
Corrected test case 2

Corrected test case 2 (previous was identical to test case 1).

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[ville.voutilainen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Ville Voutilainen <ville.voutilainen at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-12-12
                 CC|                            |ville.voutilainen at gmail dot com
     Ever confirmed|0                           |1
      Known to fail|                            |4.8.2, 4.9.1, 5.0

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The member array case only fails when the array element has a user-defined
destructor

Here's the failing testcase repeated from the attachment and reduced slightly:

struct Child
{
    Child (int);
    ~Child ();
    Child (const Child &) = delete;
};

struct Parent
{
    Parent () : children {{5}, {7}} {}

    Child children[2];
};


i.cc: In constructor ‘Parent::Parent()’:
i.cc:12:35: error: use of deleted function ‘Child::Child(const Child&)’
     Parent () : children {{5}, {7}} {}
                                   ^
i.cc:6:5: note: declared here
     Child (const Child &) = delete;
     ^

Commenting out the destructor declaration allows it to compile.
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Subject: [Bug target/64829] [ARM] ICE at -O3 in vect_get_vec_def_for_stmt_copy
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idd829

--- Comment #4 from ktkachov at gcc dot gnu.org ---

>
> are you sure it isn't already fixed?

Don't think so. It ICEs for me with r220203.
I'm using the options -mfpu=neon -mfloat-abi=hard  -O3 -march=armv7-a.
The -mfloat-abi=hard is important, it doesn't reproduce without it

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |cth027 at yahoo dot de

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
*** Bug 64887 has been marked as a duplicate of this bug. ***

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced from PR 64887:

struct string
{
  string(const char*) { }
  ~string(); // make this type non-trivial
};

struct A
{
  string s;
  A() = delete;
  A(const A&) = delete;
  A(A&&) = delete;
  A(const char*);
};

A arr[2] = {{"a"}, {"b"}}; // ok

struct Aggr {
  A arr[2];
  Aggr() : arr{{"a"}, {"b"}} {} // error
};

The member of non-trivial type is required to trigger the error, presumably
because it makes the destructor non-trivial.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[eyalroz at technion dot ac.il]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Eyal Rozenberg <eyalroz at technion dot ac.il> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |eyalroz at technion dot ac.il

--- Comment #12 from Eyal Rozenberg <eyalroz at technion dot ac.il> ---
Rejection valid code, especially valid code which is not contrived and can well
occur in people's real-life work, seems like a high-priority bug.

The last substantive comment here, other than dupe-marking-related comments two
years ago, is comment #8, asking for this to be fixed - four and a half years
ago.

Jonathan and others - please try to prioritize fixing this, and even if you
can't for some reason - at least explain which this can't be fixed promptly.

See also:

https://stackoverflow.com/q/65138048/1593077

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
At least for #c5 the important difference between that testcase and // ~Child
();
which is accepted is I think since
r0-113052-ge2df21bfc6c81b4bc410a42002c8427454ffa628
in the cp/init.c (perform_member_init) code:
888           /* A FIELD_DECL doesn't really have a suitable lifetime, but
889              make_temporary_var_for_ref_to_temp will treat it as automatic
and
890              set_up_extended_ref_temp wants to use the decl in a warning. 
*/
891           init = extend_ref_init_temps (member, init, &cleanups);
892           if (TREE_CODE (type) == ARRAY_TYPE
893               && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (type)))
894             init = build_vec_init_expr (type, init, tf_warning_or_error);
If it has trivial destructor, nothing calls build_vec_init_expr and the copy
ctor isn't needed, but when it is called, it is needed.
I think in this case extend_ref_init_temps doesn't do anything at all, so it is
unclear if build_vec_init_expr is needed too or not.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[pdimov at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Peter Dimov <pdimov at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pdimov at gmail dot com

--- Comment #14 from Peter Dimov <pdimov at gmail dot com> ---
FWIW, I just hit this problem as well when trying to make changes to
Boost.Variant2. My reduced test case is https://godbolt.org/z/zG6ddP; I was
going to submit that as a bug but found this one.

I support the petition to have this fixed.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |mpolacek at gcc dot gnu.org
                 CC|                            |mpolacek at gcc dot gnu.org

--- Comment #15 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Looking.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|mpolacek at gcc dot gnu.org        |jason at gcc dot gnu.org
                 CC|                            |jason at gcc dot gnu.org

--- Comment #16 from Jason Merrill <jason at gcc dot gnu.org> ---
Mine.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:cd09079cfd50d289cbb05eadb728a0713f6bae8a

commit r11-6733-gcd09079cfd50d289cbb05eadb728a0713f6bae8a
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jan 15 11:42:00 2021 -0500

    c++: Fix list-init of array of no-copy type [PR63707]

    build_vec_init_elt models initialization from some arbitrary object of the
    type, i.e. copy, but in the case of list-initialization we don't do a copy
    from the elements, we initialize them directly.

    gcc/cp/ChangeLog:

            PR c++/63707
            * tree.c (build_vec_init_expr): Don't call build_vec_init_elt
            if we got a CONSTRUCTOR.

    gcc/testsuite/ChangeLog:

            PR c++/63707
            * g++.dg/cpp0x/initlist-array13.C: New test.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |11.0
      Known to fail|11.0                        |

--- Comment #18 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed for GCC 11 so far.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #19 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:81fd2df5911c4b2c31960fa5ef1407d20f1ca50c

commit r10-9311-g81fd2df5911c4b2c31960fa5ef1407d20f1ca50c
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jan 15 11:42:00 2021 -0500

    c++: Fix list-init of array of no-copy type [PR63707]

    build_vec_init_elt models initialization from some arbitrary object of the
    type, i.e. copy, but in the case of list-initialization we don't do a copy
    from the elements, we initialize them directly.

    gcc/cp/ChangeLog:

            PR c++/63707
            * tree.c (build_vec_init_expr): Don't call build_vec_init_elt
            if we got a CONSTRUCTOR.

    gcc/testsuite/ChangeLog:

            PR c++/63707
            * g++.dg/cpp0x/initlist-array13.C: New test.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #20 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:ca02f0a0eb0fbeb3c1e01c3a55a95b0690ecfabc

commit r9-9212-gca02f0a0eb0fbeb3c1e01c3a55a95b0690ecfabc
Author: Jason Merrill <jason@redhat.com>
Date:   Fri Jan 15 11:42:00 2021 -0500

    c++: Fix list-init of array of no-copy type [PR63707]

    build_vec_init_elt models initialization from some arbitrary object of the
    type, i.e. copy, but in the case of list-initialization we don't do a copy
    from the elements, we initialize them directly.

    gcc/cp/ChangeLog:

            PR c++/63707
            * tree.c (build_vec_init_expr): Don't call build_vec_init_elt
            if we got a CONSTRUCTOR.

    gcc/testsuite/ChangeLog:

            PR c++/63707
            * g++.dg/cpp0x/initlist-array13.C: New test.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Jason Merrill <jason at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |9.4

--- Comment #21 from Jason Merrill <jason at gcc dot gnu.org> ---
Also fixed for 9.4 and 10.3.

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[eyalroz1 at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

--- Comment #22 from Eyal Rozenberg <eyalroz1 at gmx dot com> ---
Thank you, Jason and others, for your attentiveness to interest in the bug and
prioritizing its fix. (Now if you could just fix all the other bugs I'm
interested in... :-P)

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |richard-gccbugzilla@metafoo
                   |                            |.co.uk

--- Comment #23 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 68709 has been marked as a duplicate of this bug. ***

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |l2m at ukr dot net

--- Comment #24 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 91499 has been marked as a duplicate of this bug. ***

[Bug c++/63707] Brace initialization of array sometimes fails if no copy constructor

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63707

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jlame646 at gmail dot com

--- Comment #25 from Martin Liška <marxin at gcc dot gnu.org> ---
*** Bug 106788 has been marked as a duplicate of this bug. ***