I'm personally pretty excited to see where this goes. It could be the best way for gccrs to version itself. There are some immediate aspects I am pretty interested in relation to the spec:

1. Method resolution

2. Unstable?

In particular is it going to define lang items?

3. DST's

Rust has strange things like:

```

let a:&str = "str";

let b:&str = &"str";

```

Which is valid since str is a DST. Although slices and dyn trait are DST they have more strict rules there.

4. Qualified paths

There are more subtle things like qualified paths such as this testcase which could be argued is valid https://github.com/rust-lang/rust/blob/master/src/test/ui/qu... but there was some discussion on zulip which clarifies it: https://rust-lang.zulipchat.com/#narrow/stream/122651-genera...

5. Never type

TLDR: Overall I think its important at some point to start isolating what is the language outside of what version of libcore your running.