How to debug D on Linux

[Roguish]

How to debug D? My little trial app gives a segmentation fault. 
Probably a null pointer somewhere, which I could find simply by 
reading my code. But I'm puzzled that the program outputs very 
little helpful info when it crashes, even though I've compiled 
with all the debug options I could find in the docs:

    -g -gs -gf -debug -d-debug

Still all I get at runtime is

    Segmentation fault (core dumped)

Surely it should be possible to get at least a stack trace?