asm-casts: Run on no_std

[chrysn]

There's nothing in the asm-casts crate that necessitates std (and the std::marker::PhantomData was changed to its alias core::marker::PhantomData). This PR just sets #![no_std] and switches over the PhantomData import.

This allows code produced with asm casts to be used in no_std environments. (Admittedly, that's a bit far-fetched as there's no official support for cross-platform transpilation yet, see #305 -- but it's another stepping stone towards rust-lang/rust-bindgen#1344).

I've tested this in a practical application (it builds and runs -- but I can't tell yet whether it actually executes any place with those casts), and run the local cargo test which runs the crate-internal coverage combo successfully.

[ahomescu]

I approved this, but we need to see what's up with that failing test (might not be caused by your change).

[chrysn]

It's the ##[error]Input required and not supplied: token error I've seen in other failed build runs as well. (The later ##[error]Cannot read property 'replace' of null might be a follow-up error from the token not being set, and thus possibly null).

Looks to me like

c2rust/.github/workflows/internal-testsuite.yml

Line 32 in ca54f19

token: ${{ secrets.GH_ACTIONS_CONTROL_PRIV_REPOS }}

is missing its input; can't do much about that from the outside as that probably needs configuring somewhere in the CI setup.

[thedataking]

The failing test is because the forked version does not have access to the repo secret needed to pass the GitHub Actions tests. I tried disabling GitHub Actions on third-party PRs but apparently I wasn't successful. Merging.

[chrysn]

Thanks for merging.

Would it be possible to upload this to crates.io? I'm approaching the release of the new c2rust based version of riot-sys, and cargo insists all dependencies are uploaded.

(The c2rust which users need to have installed depends on, basically, all the other PRs I currently have open, but that's not so bad because that dependency is outside cargo anyway as c2rust can't be a build dependency AFAIU, but the c2rust-asm-casts are a regular dependency).

[ahomescu]

Pinging @rinon for crates.io releases.

[chrysn]

@rinon, is there anything left to do / where I contribute to getting this to crates.io? That dependency is currently the largest stopper to a new round of RIOT sys-/wrapper crates being published.

[rinon]

@chrysn new version is published, sorry it took so long.

[chrysn]

I still see https://crates.io/crates/c2rust-asm-casts as being the 0.1.1 of last 2019-10-30, might something have gone wrong during the upload?

[rinon]

I was dumb and missed this crate in the publish. Should be good now @chrysn