Confused about coroutine behavior

[Rebecca Ribas]

Hi gcc list,

I'm learning c++ coroutines but I ran into a behavior that I can't make
sense of.

Here is the godbolt link: https://godbolt.org/z/rdPo8ceKP

In some cases, it appears that temporaries are incorrectly freed, the code
shows test1 and test2 that works as expected, but test3 raises a "used
after free" error from address sanitizer that doesn't make sense to me.

I'm aware that there are some potential caveats with passing references to
a coroutine, so I'm possibly missing some subtle detail. But it looks like
it might be a gcc bug since the same doesn't happen with clang.

I tested a few different versions of g++ available on ubuntu and godbolt
but got the same result.

The compilations flags I used were: -ggdb3 -Og -std=c++20 -Wall -Wextra
-Werror -D_GLIBCXX_DEBUG -fsanitize=address

Cheers!