access control for withfield bytecode, compared to putfield

[Dan Smith]

> On Apr 8, 2020, at 11:29 PM, John Rose <john.r.rose at oracle.com> wrote:
> 
> To summarize:  The simplest rule for access checking a
> withfield instruction is to say, “pretend the field was
> declared private, and perform access checks”.  That’s
> it; the rest follows from the rules we have already laid
> down.

Just had a chance to read this old mail...

FWIW, this *is* the specified behavior in the most recent JVMS iteration:

http://cr.openjdk.java.net/~dlsmith/lw2/lw2-20190628/specs/inline-classes-jvms.html#jvms-6.5.withfield

I agree, private access seems to be the right model. (Plus, maybe at some point, giving the class file the ability to express a 'withfield' access restriction as one of { public, protected, package, private }.)