Nothing breaks, the library module has to have a module name. \lib\blah.d: module lib.blah;
\blah.d:
module blah;
import lib.blah;
void main() { }
$ rdmd blah.d
works fine.
Nothing breaks, the library module has to have a module name. \lib\blah.d: module lib.blah;
\blah.d:
module blah;
import lib.blah;
void main() { }
$ rdmd blah.d
works fine.