miri clippy failing on Windows

[RossSmyth]

Currently Clippy on Windows fails because of Windows specific code in
https://github.com/rust-lang/miri/blob/bffd41b00bf593bcf655e16748e223f8302f3de0/src/shims/os_str.rs

Clippy Warnings

PS C:\Users\Ross\Documents\miri> .\miri clippy $ cargo +miri clippy --manifest-path C:\Users\Ross\Documents\miri\Cargo.toml --all-targets warning: casting `u8` to `u16` may become silently lossy if you later change the type --> src\shims\os_str.rs:282:58 | 282 | if converted.get(1).copied() == Some(b':' as u16) | ^^^^^^^^^^^ help: try: `u16::from(b':')` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless note: the lint level is defined here --> src\lib.rs:46:5 | 46 | clippy::cast_lossless, | ^^^^^^^^^^^^^^^^^^^^^

warning: casting u8 to u16 may become silently lossy if you later change the type
--> src\shims\os_str.rs:283:62
|
283 | && converted.get(2).copied() == Some(b'/' as u16)
| ^^^^^^^^^^^ help: try: u16::from(b'/')
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless

warning: casting u8 to u16 may become silently lossy if you later change the type
--> src\shims\os_str.rs:287:45
|
287 | converted.insert(0, b'/' as u16);
| ^^^^^^^^^^^ help: try: u16::from(b'/')
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless

warning: casting u8 to u16 may become silently lossy if you later change the type
--> src\shims\os_str.rs:293:58
|
293 | if converted.get(0).copied() == Some(b'\' as u16)
| ^^^^^^^^^^^^ help: try: u16::from(b'\\')
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless

warning: casting u8 to u16 may become silently lossy if you later change the type
--> src\shims\os_str.rs:294:62
|
294 | && converted.get(2).copied() == Some(b':' as u16)
| ^^^^^^^^^^^ help: try: u16::from(b':')
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless

warning: casting u8 to u16 may become silently lossy if you later change the type
--> src\shims\os_str.rs:295:62
|
295 | && converted.get(3).copied() == Some(b'\' as u16)
| ^^^^^^^^^^^^ help: try: u16::from(b'\\')
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless

Clippy should be run in CI for all cfgs. In an ideal world the only change that would be needed would be changing this

miri/.github/workflows/ci.yml

Line 127 in bffd41b

run: ./miri clippy -- -D warnings

to this

 run: ./miri clippy --target x86_64-pc-windows-msvc --target x86_64-unknown-linux-gnu --target x86_64-apple-darwin -- -D warnings 

and whatever other targets are needed.

But there is an issue with this. You need to install the stdlib for each target. The typical way is with rustup and running, for example, rustup target add aarch64-apple-darwin. But this is not supported for custom toolchains like +miri.

I guess we can build a sysroot for each target then run clippy?

[RalfJung]

The toolchain for this job is installed here. It should be possible to install additional targets there.

[RossSmyth]

Well I can't run it on my computer because jemalloc fails to build for some reason when cross checking. I'll just see if CI can do it.

[RossSmyth]

Oh, yeah.
tikv/jemallocator#22