Program crash: GC destroys an object unexpectedly

[eugene]

On Monday, 13 September 2021 at 17:18:30 UTC, eugene wrote:
> And the most strange thing is this

It is echo-server/echo-client pair.
And it is echo-client that crashes upon SIGINT.

echo-server contains very similar code

class Listener : StageMachine {

     enum ulong M0_WORK = 0;
     enum ulong M1_WORK = 1;
     enum ulong M0_GONE = 0;

     RestRoom workerPool;
     ushort port;
     TCPListener reception;
     Signal sg0, sg1;

     this(RestRoom wPool, ushort port = 1111) {
         super("LISTENER");
         workerPool = wPool;
         this.port = port;

         Stage init, work;
         init = addStage("INIT", &listenerInitEnter);
         work = addStage("WORK", &listenerWorkEnter);

         init.addReflex("M0", work);

         work.addReflex("L0", &listenerWorkL0);
         work.addReflex("M0", &listenerWorkM0);
         work.addReflex("S0", &listenerWorkS0);
         work.addReflex("S1", &listenerWorkS1);
     }

     void listenerInitEnter() {
         reception = newTCPListener(port);
         sg0 = newSignal(Signal.sigInt);
         sg1 = newSignal(Signal.sigTerm);
         msgTo(this, M0_WORK);
     }

but it does not crashes (destruc).

The only significant difference - it has TCPListener instance, 
besides absolutely the same sg0 and sg1 'channels'.