[Bug ada/123861] New: ICE on compare with anonymous empty vector

[jesper.quorning at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123861

            Bug ID: 123861
           Summary: ICE on compare with anonymous empty vector
           Product: gcc
           Version: 15.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jesper.quorning at gmail dot com
                CC: dkm at gcc dot gnu.org
  Target Milestone: ---

Hi again :-),

Stumbled into an ICE reproduced with this minimal program: 

```ada
with Ada.Containers.Vectors;

procedure Ice_Compare 
is
   package Integer_Vectors is new
     Ada.Containers.Vectors (Index_Type   => Positive,
                             Element_Type => Integer);
   use Integer_Vectors;

   A : constant Vector  := [];
   B : constant Boolean := [] = A;        -- ICE
   C : constant Boolean := Vector'[] = A; -- Works
   D : constant Boolean := A = [];        -- Works
begin
   null;
end Ice_Compare;
```

Build with:

$ gnatmake -gnat2022 ice_compare.adb

Top of bug box:

+===========================GNAT BUG DETECTED==============================+
| 15.2.0 (x86_64-apple-darwin22.6.0) Constraint_Error erroneous memory access|
| Error detected at ice_compare.adb:11:28                                  |
| Compiling ice_compare.adb                                                |

Seems to work with GNAT 14.2.


Thanks