Does dmd's -i "include imported modules in the compilation" switch generate object files?

[Ali Çehreli via Digitalmars-d-learn]

-i is a useful feature:

  https://dlang.org/dmd-linux.html
Does dmd compile auto-included files separately? Does it generate 
temporary object files? If so, where does it write the files? Would -i 
cause race conditions on the file system?

Thank you,
Ali