[javac] assert false : "Should never have gotten here.";
If I remove it, I will probably screw up while maintaining the code, and suddenly make it possible to get there. But then I have no assert. Sensible suggestions appreciated.
Update: It's ugly, but: Make the function non-void, make all return points explicit, and make this location be a default return without a value. Then at least I'd get a "Needs return statement" error. I do not intend to do this. Other suggestions appreciated.