Questions concerning hierarchical module system

[Wolfgang Jeltsch]

Hi,
I have some questions regarding the hierarchical module system now 
implemented in Hugs as well as in GHC.
Currently it is possible to have a module A1.A2. ... .Am and a module A1.A2. 
... .Am. ... .An (n > m) at the same time. The first one's source code would 
be in file <root>/A1/A2/ ... /Am.hs and the second one's in file 
<root>/A1/A2/ ... /Am/ ... /An.hs. So there would be both a Am.hs file and a 
Am directory in the same directory. A1.A2. ... .Am would have two meanings: a 
module and a "module container". Hugs and GHC doesn't seem to have problems 
with this. But I want to know if I can rely on this behaviour still beeing 
present in future implementations and if this kind of module organisation is 
maybe considered bad practice.

Wolfgang