* Should we make it possible to use the new expression switch
construct in non-expression contexts? Any values returned by a
case would be ignored. Optionally we could skip requiring default
to be present (meh). Users may want this because it's really nice
to not have to write "break" anymore. They may also want it if we
answer "no" to either or both of the previous two questions. It's
also kind of nice that each case gets its own separate scope,
although they can get that by inserting braces anyway.
In order for it not to be painful to turn a statement switch into an
expression switch, we'd have to support void-typed expression switches.
Then you could write something like this:
switch (target) {
case X -> println("x");
case Y -> println("y");
}
But expressions can't have void type (among other reasons, it's not a
type, at least not yet), so we'd have to carve out a special case for
this if we wanted to support it. And this would further muddy the
differences, and call for a number of other special cases (e.g., how
would I write the default clause?)
So as long as we don't bend over backwards to try and special-case void
expression switches (we don't for conditional expressions), I think
"there's expression switch and statement switch; using either to
simulate the other is painful, so don't" leads to a good place.
(Note to observers: the goal of this exercise here is not to fix what
people hate about statement switch; it's about (a) laying the groundwork
for pattern matching while (b) factoring out some generally-useful
enhancements that can be exposed earlier.)
