Taking y'all's suggestions. I saw that dropRight makes a wrapper; it's not an extension method despite AnyVals.  You don't have to tell me here why, either I'll figure it out and/or use SO.  But what bytecode to expect wasn't obvious.  Now, at least, I can try it in the repl and just javap f to see what it looks like.

Thanks for the attention.  Additional commit with tests coming in a few.