Is the use of .di depreceated ?

["Erèbe"]

Hi,

I recently discovered that D support file interface .di, but 
through my past reads I never seen someone using it. The std 
don't do usage of it (compile time issue maybe ?) and most of D 
project are in the same case.

Is this feature depreceated ?

I'm from a C++ background, I agree on the fact that keeping 
declarations and implementaions sync across two files is tedious, 
but when I have to read code, I like a clean interface to 
summarize the thing.

Dmd doc is there to replace the need of an clean interface ?