[Bug c++/104670] New: ICE when using decltype of a lambda returning a struct inside of a struct

[Bug c++/104670] New: ICE when using decltype of a lambda returning a struct inside of a struct

[krzysio.kurek at wp dot pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

            Bug ID: 104670
           Summary: ICE when using decltype of a lambda returning a struct
                    inside of a struct
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: krzysio.kurek at wp dot pl
  Target Milestone: ---

Created attachment 52502
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52502&action=edit
-freport-bug output

GCC ICEs when compiling the following piece of code:

struct foo {
    decltype([] { return (struct {
        int fn() {}
    }){}; }) bar;
};

Compiled with `-std=c++20`
Past stable releases of GCC report "confused by earlier errors, bailing out"
without crashing instead.

[Bug c++/104670] ICE when using decltype of a lambda returning a struct inside of a struct

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to krzysio.kurek from comment #0)
> Compiled with `-std=c++20`
> Past stable releases of GCC report "confused by earlier errors, bailing out"
> without crashing instead.

Right. That means it was an internal compiler error after an error message.
That happens with released gcc where gcc is configured by default to
--enable-checking=release .
So this is not a regression.

[Bug c++/104670] ICE when using decltype of a lambda returning a struct inside of a struct

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-02-23
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=39751
           Keywords|                            |error-recovery,
                   |                            |ice-checking,
                   |                            |ice-on-invalid-code

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

[Bug c++/104670] [9/10/11/12 Regression] ICE when using decltype of a lambda returning a struct inside of a struct

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |mpolacek at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
            Summary|ICE when using decltype of  |[9/10/11/12 Regression] ICE
                   |a lambda returning a struct |when using decltype of a
                   |inside of a struct          |lambda returning a struct
                   |                            |inside of a struct
           Priority|P3                          |P4
   Target Milestone|---                         |9.5

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Well, it is a regression since
r9-4045-g0c1e0d63fe0ceabbd04384070f3b59f8bf50de09
because before that we rejected the testcase, now we rejecte it for a different
reason and ICE during error recovery.
But error recovery ICEs are lower priority.

[Bug c++/104670] [10/11/12/13 Regression] ICE when using decltype of a lambda returning a struct inside of a struct

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.5                         |10.4

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9 branch is being closed

[Bug c++/104670] [10/11/12/13 Regression] ICE when using decltype of a lambda returning a struct inside of a struct

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |10.5

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.

[Bug c++/104670] [11/12/13/14 Regression] ICE when using decltype of a lambda returning a struct inside of a struct

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.5                        |11.5

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10 branch is being closed.

[Bug c++/104670] [11/12/13/14 Regression] ICE when using decltype of a lambda returning a struct inside of a struct

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104670

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
   Target Milestone|11.5                        |12.0
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=101911
         Resolution|---                         |FIXED
           Keywords|                            |c++-lambda
             Blocks|                            |107430

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed in GCC 12.

Note you can make this an ICE after an invalid error with:
```
struct foo {
    decltype([] {  struct a{
        int fn() {}
    }; a{}; }) bar;
};
```

But that is really PR 101911 .

So still closing as fixed.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107430
[Bug 107430] [meta-bug] lambda in decltype