[RFA v2 3/4] Convert Rust to use discriminated unions

[Tom Tromey]

>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:

Pedro> I was comparing test results from 20180207 and today, I
Pedro> noticed that gdb.rust/simple.exp regressed:

Thanks.

Pedro> I haven't bisected, but the references to discriminant info make me suspect
Pedro> this patch I'm replying to.

Yeah, it has to be.

Pedro> This is Fedora 27 with:
Pedro>  $ rustc --version
Pedro>  rustc 1.13.0 (2c6933acc 2016-11-07)

I will look into it tomorrow.

Tom