"--" is almost universally used as a decrementing operator, and it's also a common prefix for verbose shell options. Just because you're now working with a different language doesn't mean that you are free to repurpose other languages' operators for entirely unrelated purposes. It's just a recipe for confusion, not to mention it's ugly.
I thought I'd seen the worst when PHP picked backslash as the namespace separator. Now it's just getting crazy. Why couldn't they just pick a normal sigil that everyone already understands, like the dollar sign?