Trying to think of a workaround for http://d.puremagic.com/issues/show_bug.cgi?id=4477 , I thought I'd duplicate DMD's lookup rules. That's daunting in itself, but I quickly found it impossible. JSON output omits import statements from modules.
An IDE could use the list of imports to detect when code is silently relying on another module's imported symbols due to bugzilla 313/314, or to find unnecessary import statements. And, of course, to work around bugzilla 4477. It's also a cheap way for an IDE to support incremental builds rather than using dmd -deps, making it essentially free to do incremental builds once you have syntax highlighting.