-d option does not work

[shoo]

The following code does not work when using -d

int main() {
	debug (TEST) {
		import std.stdio;
		writeln("DEBUGGING");
		return 0;
	} else {
		return 1;
	}
}

Running:

dub run -d=TEST 

results in:

       Error Error processing arguments: Can't parse string: bool should be case-insensitive 'true' or 'false'
             Run 'dub help' for usage information.

However, this command works as expected:

dub run --debug=TEST

Currently, -d is documented as an alias for --debug.
But there is also an undocumented option, --deep, which also assigns -d as an alias. This leads to a conflict:

  -d  --deep            Build all dependencies, even when main target is a
                        static library.
  -d  --debug=VALUE     Define the specified `debug` version identifier when
                        building - can be used multiple times

I believe this conflict is the reason why -d does not work as intended.
If that is the case, I suggest removing the -d alias from --deep.