Comment 34 for bug 305176

Google ref: b/16983603.

I wouldn't call this bug fixed.

I have just found ~30 bugs in our code, where someone wrote:

  vector<int> v;
  ...
  v.empty(); // v.clear() was intended!

No problem, I'll just add warn_unused_result to vector::empty(), right?

Well, that did expose the 30 bugs above, but unfortunately I can't do that permanently, because it also exposed this false positive:

   assert(v.empty());

where assert in NDEBUG mode expanded into

  static_cast<void>(v.empty());

and triggered the warning :-(

P.S. Some of the bugs I found were in parts of the code imported from open-source projects, so it's not a problem that is specific to just Google. If the assert problem could be addressed, adding warn_unused_result to trunk libstdc++ would benefit everyone.