On Mar 13, 2018, at 5:23 PM, John Rose <john.r.r...@oracle.com> wrote: > > Also, even for e-switches an explicit exhaustiveness marker is > desirable. For both kinds of switches, there are cases where > the user wants to say, "I know I have covered all the possibilities" > and thus turn off the effects of exhaustiveness checking, including > DA rules and whatever DA-like rule we define for e-switches.
P.S. You probably surmised, correctly, that this involves injecting an implicit exception throw, at an implicit default. Whether the compiler asserts exhaustivness from type analysis, or the user asserts it just because, the runtime has to have a backup plan to throw a MatchError or SurpriseInSwitchError, to keep the JVM's verifier happy.