Dummy template parameter vs empty template parameter list

[Ben Jones]

Looking through Phobos code there's a bunch functions defined 
with dummy template types:

void whatever(TDummy = void)( int x, ...) //TDummy is never used

Why not just use an empty template parameter list?

void whatever()(int x, ...)


My gut tells me that his is a workaround for an old limitation 
preventing empty template lists, but figured I'd ask.