Weird linker error with exit code 1

[terchestor]

I've searched for previous posts about that linker error exit 
code 1 without finding any valuable solution.
I'm compiling and unittesting a module importing other modules 
already tested without any error.
I get a linker error with one of my imported modules (named 
tausworthe). However I dont have that error when I import the 
tausworthe module in another similar module. I can't figure out 
the source of the error.
----
dmd -unittest -debug=Generator -main generator.d
generator.o:(.data+0xc0): undefined reference to 
`_D10tausworthe12__ModuleInfoZ'
generator.o: In function 
`_D6signal13__T6SignalTeZ6Signal4��atMFNdmZv':
__main.d:(.text._D6signal13__T6SignalTeZ6Signal4��atMFNdmZv+0x67): 
undefined reference to `_D6signal8__assertFiZv'
----