Yeah, what kind of strong typing is going to keep you from NOT calling a function?
The research into this is usually called "effect systems", I think. You can use it to prove that ugly old APIs like OpenGL are being used properly in your code.
As far as the real world goes, all you get is -Wunused.
Adding annotation @CheckResult on
android.widget.Toast#makeText(android.content.Context, java.lang.CharSequence, int)