Fix `attempted to read from stolen value`

[W95Psp]

The frontend browses items of a crate in an order that causes this bug.
Some data in the Rust compiler is kept in a Steal, which is basically a box whose content can be stolen, that is pulled out of the memory (rustc uses arenas)

Thus, the order in which we browse the crate to export every item matters: sometimes I inspect things that happens to be stolen before because of some previous inspections.
This is particularly true for constants, it seems.

Status: mostly fixed

• @geonnave's bug (Fix attempted to read from stolen value #27 (comment)) is fixed
• @franziskuskiefer's bug (Fix attempted to read from stolen value #27 (comment)) is fixed

However, I tried Hax on core, and I get new stolen stuff. Thus, there exists some scenarios in which this still fails.

[geonnave]

For the record (context from #99):

• this issue also affects translation of the edhoc-rs crate into fstar.
• in fstar generation fails with Unimplemented on array! macro #99 there is a How to reproduce section, that could be validated against once this issue is addressed.

[franziskuskiefer]

Another code snippet that panics

#[repr(u16)]
pub enum ProtocolVersion {
    Mls10 = 1,
}

impl ProtocolVersion {
    #[allow(non_upper_case_globals)]
    fn tls_deserialize(bytes: &[u8]) -> core::result::Result<(Self, &[u8]), tls_codec::Error> {
        const __TLS_CODEC_Mls10: u16 = ProtocolVersion::Mls10 as u16;
        let (discriminant, remainder) =
            <u16 as tls_codec::DeserializeBytes>::tls_deserialize(bytes)?;
        match discriminant {
            __TLS_CODEC_Mls10 => {
                let result = ProtocolVersion::Mls10 {};
                Ok((result, remainder))
            }
            _ => Err(tls_codec::Error::UnknownValue(discriminant.into())),
        }
    }
}

[W95Psp]

Another stealing bug (from issue #474):

https://github.com/hacspec/hax/blob/aa14fb139280e7fcd28acb45db27b01b53c9de93/tests/rust-ast/src/lib.rs#L14-L20

Originally posted by @franziskuskiefer in #474 (comment)

Open this code snippet in the playground

Status: works OK in 8ab62258df ✅