This is really a DSSS/rebuild bug, and I've already filed a ticket, but I submit this as a potential enhancement here since:
- the main page says that D1/Tango is no longer supported anyway
- a simple removal of a Tango import will solve the problem as a stopgap until the bug in rebuild is fixed
qt/qtd/Traits.di contains an import of tango.core.Traits, which is compiled only if using D1. The problem is that rebuild will see the import, but not the conditional compilation, and will thus fail to build the project unless Tango is installed.
As I said, this is a problem with rebuild, but in the meantime, would it make sense to just remove the import from qtd, since presumably it is no longer needed? I think this small change would likely be much quicker than waiting for rebuild to be fixed. :-)