[Bug c++/105901] New: [C++20] Code generation bug. Well-formed Program segfaults.

[benni at stuerz dot xyz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105901

            Bug ID: 105901
           Summary: [C++20] Code generation bug. Well-formed Program
                    segfaults.
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: benni at stuerz dot xyz
  Target Milestone: ---

Created attachment 53105
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53105&action=edit
The full source code.

GCC versions at least 10.1 to 12.1 (and trunk on godbolt.org) are affected.
System Type: Linux (x86_64)
Build with: g++ -std=c++20 -Wall -Wextra
The optimization level doesn't matter. And the compiler produces no warnings.
Substituting g++ with clang++ makes it work.

The attached file is a small project of mine to create a type-eraser for
"Printable things".

The expected output of the program:
[[10, 20, 30], Hello World, [A random struct (1), A random struct (2), A random
struct (3)]]