Call for feedback -- enhanced switch

[Brian Goetz]

> BTW, it remember me something i have forgotten to ask, for both ecj and javac, when you compile with --enable-preview, all the classes have they minor version changed even the one that doesn't use the switch expression. I've tried to find where this behaviour was documented in the JEP 12 [2] but the "compile-time" section is not clear about that.

That's correct.  This is not unlike compiling with -source/-target N; 
even if it doesn't use any features added in N, it writes out that 
version of the classfile.  This is predictable for users and way simpler 
for compilers.  The alternative is getting into an interpretation of 
"could this classfile run on a different version", whose 
complexity/benefit ratio would be way out of balance.