Known reasons why D crashes without any message?

[rikki cattermole via Digitalmars-d]

1) You really need to switch to ldc, even for small neural networks, it 
makes a MASSIVE difference!
2) In release mode, who knows what'll happen. Add some logging in maybe 
(versioned/debug of course) to help figure out where things are going on.
3) Wrap it up with try catch and write out the message yourself. You 
want Error not Exception FYI.

Not terribly helpful, but a good place to begin anyway.
Of course if somebody is calling the c exit function, it may very well 
bypass D's exception handling all together.