Why does logging in destructor lead to segmentation fault?

[Vladimir Marchevsky]

On Monday, 11 September 2023 at 18:08:45 UTC, Bradley Chatha 
wrote:
> What's happening is that the GC is running the dtors for all 
> objects after the main function's finished in a final cleanup, 
> which prevents you from allocating any GC memory without 
> crashing.
>
> Potentially as well the GC has already cleaned up the 
> `sharedLogger` causing the null read.

What's confusing me is that debugger stops exactly on 
`synchronized(mutex)` line inside of `log` implementation. Does 
this operation allocate any GC memory?.. Also looking through 
locals in debugger, logger object seems to be fine (otherwise it 
would crash earlier, I guess?.. At least, `this` points to 
something at non-zero address), `mutex` looks alive as well. 
Isn't it wrong to have something garbage-collected while object 
containing it is still alive?