[Bug c++/113263] New: ICE for invalid code for compound literal and type definition in return type

[Bug c++/113263] New: ICE for invalid code for compound literal and type definition in return type

[muecker at gwdg dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113263

            Bug ID: 113263
           Summary: ICE for invalid code for compound literal and type
                    definition in return type
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: muecker at gwdg dot de
  Target Milestone: ---

The following example ICEs after invalid code (it is valid C but not C++)

https://godbolt.org/z/7zrbxPraM
(partially minimized from: C example https://godbolt.org/z/M7n7o1r8h)

#define TOKEN_CONCAT_EX(x, y) x##y
#define TOKEN_CONCAT(x, y)    TOKEN_CONCAT_EX(x, y)
#define UNIQUIFY(x)           TOKEN_CONCAT(x, __LINE__)

#define ResultBody(T, E) { bool _is_ok; union { T _ok; E _err; }; }
#define ResultName(T, E) result_##T##_##E
#define ResultEx(T, E, T_N, E_N) struct ResultName(T_N, E_N) ResultBody(T, E)
#define Result(T, E) ResultEx(T, E, T, E)

#define Err(R, V) ((R) { ._is_ok = false, ._err = V, })


typedef struct
{
  int val;
} thing_t;

Result(thing_t, bool) maybe_make_thing(int v)
{
   return Err(Result(thing_t, bool), v == 200);
}

[Bug c++/113263] ICE for invalid code for compound literal and type definition in return type

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113263

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 57004
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57004&action=edit
Preprocessed source

[Bug c++/113263] ICE for invalid code for compound literal and type definition in return type

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113263

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|                            |ice-checking,
                   |                            |ice-on-invalid-code
   Last reconfirmed|                            |2024-01-08

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
It has nothing to do with the return type.
Rather it is just an initialization that is causing the issue with the type
defined there and an anonymous union.

Reduced testcase:
```
void
maybe_make_thing(void)
{
   (struct { union {  bool _err; }; })
     {  ._err = 1, } ;
}
```

Confirmed, looks like it is only and ICE with checking too.
```
<source>: In function 'void maybe_make_thing()':
<source>:5:20: error: 'maybe_make_thing()::<unnamed union>::_err' is not a
direct member of 'maybe_make_thing()::<unnamed struct>'
    5 |      {  ._err = 1, } ;
      |                    ^
```