[Bug c++/102740] New: [11.2/12 Regression] Data member not found in struct inside an unnamed union

[Bug c++/102740] New: [11.2/12 Regression] Data member not found in struct inside an unnamed union

[curdeius at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

            Bug ID: 102740
           Summary: [11.2/12 Regression] Data member not found in struct
                    inside an unnamed union
           Product: gcc
           Version: 11.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: curdeius at gmail dot com
  Target Milestone: ---

Reproduce on godbolt: https://godbolt.org/z/3frPbPj35.

This snippet of code works ok on gcc 11.1, but fails to compile on gcc 11.2 and
trunk (12).

```
typedef struct {
    union {
        struct {
            const void* content;
        } put;
    };
} op_t;

op_t f(const char* alias) {
    return op_t{
        .put =
            {
                .content = alias,
            },
    };
}
```

The error message (compiled with `-std=c++20` but the standard version seems
irrelevant):
```
<source>: In function 'op_t f(const char*)':
<source>:15:5: error: 'op_t::<unnamed union>' has no non-static data member
named 'content'
   15 |     };
      |     ^
Compiler returned: 1
```

>From the error message, it seems that the compiler searches for `content` data
member inside the unnamed union and not in the unnamed `put` struct.

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[curdeius at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

--- Comment #1 from Curdeius Curdeius <curdeius at gmail dot com> ---
Also, the bug doesn't appear (or TBH, it's a different bug), when the unnamed
union contains a `content` data member. But it seems to be a bug then as well,
because it's not what is intended to be initialized.

Also, the bug doesn't appear without union.

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.4
     Ever confirmed|0                           |1
      Known to fail|                            |11.2.0
   Last reconfirmed|                            |2021-10-14
      Known to work|                            |10.3.0, 11.1.0
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=100489
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Just like PR 101767, so this is most likely caused by the patch which fixes PR
100489 so this is a regression in 10.4.0 also.

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[curdeius at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

--- Comment #3 from Curdeius Curdeius <curdeius at gmail dot com> ---
For other users with this problem, a workaround is to use a named struct. So
here, it would look like:
```
typedef struct {
    const void* content;
} put_t;

typedef struct {
    union {
        put_t put; // named struct
    };
} op_t;

op_t f(const char* alias) {
    return op_t{
        .put =
            put_t{ // named explicitly
                .content = alias,
            },
    };
}
```

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |roland at gnu dot org

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 103290 has been marked as a duplicate of this bug. ***

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

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

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r12-954.  (Bug 101405 also started with that rev.)

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

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

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

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

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=103337

--- Comment #6 from Patrick Palka <ppalka at gcc dot gnu.org> ---
PR103337 contains a related testcase which we reject with a similar error, and
interestingly that one isn't a regression.

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

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

[Bug c++/102740] [10/11/12 Regression] Data member not found in struct inside an unnamed union

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

--- Comment #7 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:24d51e749570dcb85bd43d3b528f58ad6141de26

commit r12-7741-g24d51e749570dcb85bd43d3b528f58ad6141de26
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Mar 21 09:57:28 2022 -0400

    c++: designated init and aggregate members [PR103337]

    Our C++20 designated initializer handling was broken with members of class
    type; we would find the relevant member and then try to find a member of
    the member with the same name.  Or we would sometimes ignore the designator
    entirely.  The former problem is fixed by the change to reshape_init_class,
    the latter by the change to reshape_init_r.

            PR c++/103337
            PR c++/102740
            PR c++/103299
            PR c++/102538

    gcc/cp/ChangeLog:

            * decl.cc (reshape_init_class): Avoid looking for designator
            after we found it.
            (reshape_init_r): Keep looking for designator.

    gcc/testsuite/ChangeLog:

            * g++.dg/ext/flexary3.C: Remove one error.
            * g++.dg/parse/pr43765.C: Likewise.
            * g++.dg/cpp2a/desig22.C: New test.
            * g++.dg/cpp2a/desig23.C: New test.
            * g++.dg/cpp2a/desig24.C: New test.
            * g++.dg/cpp2a/desig25.C: New test.

[Bug c++/102740] [11 Regression] Data member not found in struct inside an unnamed union

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |11.3
            Summary|[10/11/12 Regression] Data  |[11 Regression] Data member
                   |member not found in struct  |not found in struct inside
                   |inside an unnamed union     |an unnamed union
           Priority|P2                          |P1
      Known to work|                            |12.0

--- Comment #8 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixed on trunk, never broken on 10 branch.

[Bug c++/102740] [11 Regression] Data member not found in struct inside an unnamed union

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:2b2f575e6f27acc0c7ba6a3affc760bf2b96a84b

commit r11-9678-g2b2f575e6f27acc0c7ba6a3affc760bf2b96a84b
Author: Jason Merrill <jason@redhat.com>
Date:   Mon Mar 21 09:57:28 2022 -0400

    c++: designated init and aggregate members [PR103337]

    Our C++20 designated initializer handling was broken with members of class
    type; we would find the relevant member and then try to find a member of
    the member with the same name.  Or we would sometimes ignore the designator
    entirely.  The former problem is fixed by the change to reshape_init_class,
    the latter by the change to reshape_init_r.

            PR c++/103337
            PR c++/102740
            PR c++/103299
            PR c++/102538

    gcc/cp/ChangeLog:

            * decl.c (reshape_init_class): Avoid looking for designator
            after we found it.
            (reshape_init_r): Keep looking for designator.

    gcc/testsuite/ChangeLog:

            * g++.dg/ext/flexary3.C: Remove one error.
            * g++.dg/parse/pr43765.C: Likewise.
            * g++.dg/cpp2a/desig22.C: New test.
            * g++.dg/cpp2a/desig23.C: New test.
            * g++.dg/cpp2a/desig24.C: New test.
            * g++.dg/cpp2a/desig25.C: New test.

[Bug c++/102740] [11 Regression] Data member not found in struct inside an unnamed union

[jason at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102740

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

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

--- Comment #10 from Jason Merrill <jason at gcc dot gnu.org> ---
Fixend for 11.3 as well.