Ohhh, fair enough, yeah I see what you're saying.
Yeah you're boned in that case I think and that's a real problem that can pop up if you want full @nogc
EDIT: Maybe not based on Max's comment
D-Plug (Audio FX plugins) is one example of having to build up a dependency stack of @nogc compatible deps, a lot of that is in-house stuff.
Not impossible but it's a commitment, at which point you may as well use something else unless you REALLY want to use D, for sure.