Integration with clippy

[ishitatsuyuki]

Clippy is quite useful for sure, and I'm looking forward to having it integrated.

[nrc]

I wonder whether this should be done on the RLS end or in the IDE plugin? The interesting bit of this is it would be nice to apply the suggested changes, but I expect that should be similar to what we will do for compiler suggestions and won't need tight RLS integration.

[KalitaAlexey]

@ishitatsuyuki,
Look at https://github.com/KalitaAlexey/vscode-rust
I have a special command for running Clippy - "Cargo: Clippy".

[Hoverbear]

I propose this can be closed. clippy is a separate project and this is more suitable to an IDE plugin.

[nrc]

clippy is a separate project and this is more suitable to an IDE plugin

Perhaps, I'm keen to track this to ensure we do get a good experience in the long run. In particular, if we are able to apply Clippy's suggestions then I want to be sure that works smoothly with the RLS.

[tomprince]

Using vscode-rust, the rls integration provides feedback as you type, but as far as I can tell, running clippy directly only provides feedback after saving. And additionally (at least currently) it appears that the clippy output doesn't get the nice interactive benefits of the RLS formatted output.

It seems like it would make sense to provide access to the clippy diagnostics through the same format as the built-in compiler diagnostics, so each IDE doesn't need to add special support for clippy.

[ishitatsuyuki]

I was able to get clippy working as a command-line argument plugin, by setting RUSTFLAGS: see clippy README.

Concerns:

• Packaging. Currently there's no way to install any dylib other than rustc's.
• Long warning messages. At least overflows (clipped 😜 ) in vscode-rust.

[nrc]

Packaging. Currently there's no way to install any dylib other than rustc's.

Long term, Clippy will be distributed with Rustup (like the RLS) so I think this won't be a a problem, but it will be a bit of a long time coming. We might need something to keep us going in the mean-time

Long warning messages. At least overflows (clipped 😜 ) in vscode-rust.

Even if these are cut off in the panel, they should be displayed in full when you hover over the squiggle, correct?

[ishitatsuyuki]

Packaging. Currently there's no way to install any dylib other than rustc's.

Long term, Clippy will be distributed with Rustup (like the RLS) so I think this won't be a a problem, but it will be a bit of a long time coming. We might need something to keep us going in the mean-time

No. While the cargo-clippy executable is magically statically linked, the plugin isn't. I don't see any short term solution to this.

Long warning messages. At least overflows (clipped 😜 ) in vscode-rust.

Even if these are cut off in the panel, they should be displayed in full when you hover over the squiggle, correct?

No, the hover message is even clipped.

[nrc]

No, the hover message is even clipped.

I wonder why Clippy messages are clipped but compiler ones are not? They should be presented through the same mechanisms

[nrc]

If anyone wants to try to tackle this for the impl period, lets discuss how we might do it.

[ishitatsuyuki]

Basically it's just the matter of how we distribute clippy, and IIRC it's going to be distributed as dylib as a part of becoming submodule of Rust.

[nrc]

Yeah, it will be distributed by Rustup like the RLS.

[oli-obk]

I don't know much about rls, but isn't it essentially just calling rustc manually (via Command::new) at some point, right? We have a drop-in replacement for rustc: clippy-driver. So if I understand this correctly, we can just set RUSTC=clippy-driver and call it a day.

/me goes experimenting

[oli-obk]

Nevermind, my knowledge is severly outdated. Last time I looked at the rls source was in April

So... since clippy is trying to eliminate the plugin-method, the best way would for rls's rustc driver to duplicate the clippy's lint injection:

https://github.com/rust-lang-nursery/rust-clippy/blob/master/src/driver.rs#L78-L111

and depend on clippy_lints. Unfortunately that would mean that clippy not compiling causes rls to not compile. That can be worked around by making clippy a cargo feature of rls. In the rustc test suite for distributing rls, the feature could then be disabled if clippy fails to build.