At the moment, when generating a module list file with the command:
build -module=module.ddoc file_1.d file_2.d ... file_n.d, if a file is specified in the command line as well as being imported in another file (say, file_2.d is imported in file_1.d as well), the build tool says "module file_2 is in multiple defined" and then enters what seems to be an infinite loop.
A more productive way of dealing with this would be to print the error message, ignore the extra inclusion and just go ahead with generating the module file. There are times when you want to build a module file for a number of .d-files without knowing exactly which is imported in which (if any).
Alternatively, you could have a switch for forcing it to ignore duplicates and go ahead with building the file.
Also, the grammar is a bit off in the error message. A better phrase would be "module x is defined multiple times" or something like that.
(ps. thanks for this feature though - it's very useful)
