Indicating incompatible modules

[Joseph Rushton Wakeling via Digitalmars-d-learn]

Hello all,

Is there a straightforward way to indicate that two modules should not be used 
together in the same program?  Preferably one that does not require editing both 
of the modules?

The application I have in mind is when one is making available an experimental 
module which is planned to replace one that already exists; it's useful for the 
experimental module to be able to say, "Hey, use me _or_ the standard module, 
but not both of us."

Any thoughts ... ?

Thanks & best wishes,

    -- Joe