Flycheck-rust just says "aborting due to 3 previous errors"

[TyOverby]

There's no actual mention of what the errors are.

This is on a project that builds without issue with cargo build

[fmdkdd]

That's a terribly unhelpful error message. Sorry for that. Can you give me the output of flycheck-compile (C-c ! C-c) for rust-cargo on this file?

[TyOverby]

cargo rustc --lib -- -Z no-trans -Z unstable-options --error-format\=json --test -L/Users/tyoverby/workspace/rust/implicit-gpu/target/debug -L/Users/tyoverby/workspace/rust/implicit-gpu/target/debug/deps
   Compiling implicit-gpu v0.1.0 (file:///Users/tyoverby/workspace/rust/implicit-gpu)
{"message":"no method named `input_buffer` found for type `&opencl::OpenClContext` in the current scope","code":null,"level":"error","spans":[{"file_name":"src/marching/mod.rs","byte_start":22827,"byte_end":22839,"line_start":67,"line_end":67,"column_start":23,"column_end":35,"is_primary":true,"text":[{"text":"        let buf = ctx.input_buffer([2, 2], &[a, b, d, c]);","highlight_start":23,"highlight_end":35}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[],"rendered":null}
{"message":"no method named `len` found for type `opencl::buffers::LineBuffer` in the current scope","code":null,"level":"error","spans":[{"file_name":"src/marching/mod.rs","byte_start":22962,"byte_end":22965,"line_start":70,"line_end":70,"column_start":46,"column_end":49,"is_primary":true,"text":[{"text":"        let mut out = vec![0.0 / 0.0; result.len()];","highlight_start":46,"highlight_end":49}],"label":null,"suggested_replacement":null,"expansion":{"span":{"file_name":"src/marching/mod.rs","byte_start":22939,"byte_end":22968,"line_start":70,"line_end":70,"column_start":23,"column_end":52,"is_primary":false,"text":[{"text":"        let mut out = vec![0.0 / 0.0; result.len()];","highlight_start":23,"highlight_end":52}],"label":null,"suggested_replacement":null,"expansion":null},"macro_decl_name":"vec!","def_site_span":{"file_name":"<vec macros>","byte_start":64999,"byte_end":65221,"line_start":1,"line_end":4,"column_start":1,"column_end":31,"is_primary":false,"text":[{"text":"( $ elem : expr ; $ n : expr ) => (","highlight_start":1,"highlight_end":36},{"text":"$ crate :: vec :: from_elem ( $ elem , $ n ) ) ; ( $ ( $ x : expr ) , * ) => (","highlight_start":1,"highlight_end":79},{"text":"< [ _ ] > :: into_vec ( box [ $ ( $ x ) , * ] ) ) ; ( $ ( $ x : expr , ) * )","highlight_start":1,"highlight_end":77},{"text":"=> ( vec ! [ $ ( $ x ) , * ] )","highlight_start":1,"highlight_end":31}],"label":null,"suggested_replacement":null,"expansion":null}}}],"children":[{"message":"items from traits can only be used if the trait is implemented and in scope; the following traits define an item `len`, perhaps you need to implement one of them:","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"candidate #1: `std::iter::ExactSizeIterator`","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"candidate #2: `core::slice::SliceExt`","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"candidate #3: `core::str::StrExt`","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"candidate #4: `rayon::par_iter::ExactParallelIterator`","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":null}
{"message":"no method named `read` found for type `opencl::buffers::LineBuffer` in the current scope","code":null,"level":"error","spans":[{"file_name":"src/marching/mod.rs","byte_start":22985,"byte_end":22989,"line_start":71,"line_end":71,"column_start":16,"column_end":20,"is_primary":true,"text":[{"text":"        result.read(&mut out).enq().unwrap();","highlight_start":16,"highlight_end":20}],"label":null,"suggested_replacement":null,"expansion":null}],"children":[{"message":"items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `read`, perhaps you need to implement it:","code":null,"level":"help","spans":[],"children":[],"rendered":null},{"message":"candidate #1: `std::io::Read`","code":null,"level":"help","spans":[],"children":[],"rendered":null}],"rendered":null}
{"message":"aborting due to 3 previous errors","code":null,"level":"error","spans":[],"children":[],"rendered":null}

Interesting that it does give the other errors that it found, but it's even more odd that those "errors" don't show up in my actual build.

[TyOverby]

Is there a way that I can see what version of rustc it's using?

In my terminal, I run the command that it gave me

cargo rustc --lib -- -Z no-trans -Z unstable-options --error-format\=json --test -L/Users/tyoverby/workspace/rust/implicit-gpu/target/debug -L/Users/tyoverby/workspace/rust/implicit-gpu/target/debug/deps

and I do get the same errors on the terminal, so it's not a mismatched rustc version.

[TyOverby]

Notice how the invocation of cargo build is fine, but the invocation of cargo rustc breaks in the same way that flycheck-compile does.

[fmdkdd]

Thanks, I can indeed reproduce by cloning your repo. Looking into it.

[TyOverby]

I think I know what's going on, and this is probably not a bug in flycheck-rust, it's just that I didn't understand how flycheck works...

1. I thought that flycheck-list-errors would list all the errors for my whole project. This is apparently not the default behavior, and it shows only errors for the current file (or global errors)
2. Those compilation errors are real but they're in a #[test] method which isn't built during cargo build but is built during cargo rustc --test
3. flycheck-rust will always show that the build failed on every file, leading me to believe that the other errors were getting swallowed (when in fact, they were just being hidden because I didn't have the correct file open).

[fmdkdd]

Ah, you beat me to it.

Point 1 has actually been brought up before. There was a PR flycheck/flycheck#972, but progress has stalled for various reasons.

Point 3 is actually an unwanted side-effect of fixing flycheck/flycheck#1182. The message "aborting due to 3 previous errors" should be filtered out by flycheck, and flycheck/flycheck#1187 should take care of it. I notice that my fix was incomplete, so thanks for your report :)

[TyOverby]

@fmdkdd Would you be willing to mentor me as I attempt to add project-wide error messages to flycheck? I'm really new to emacs lisp and it looks like you know your way around flycheck + flycheck-rust!

Unfortunately flycheck is basically worthless for me until it has project-wide error messages, so I'm going to try and add it myself 😄

[fmdkdd]

@TyOverby That's actually a feature that I would like to see implemented as well. From a cursory reading of the PR discussion, it does not look like an easy task to complete. But, that PR in its current state may be a good place to start.

I don't know flycheck inside-out, but I can follow the lisp. I'll be happy to help you out, but expect more than a few bumps in the road before we manage to work out all the corner cases :)

Open up a PR on flycheck/flycheck proper. I think the approach taken in flycheck/flycheck#972 is sound and was already approved. It just needs polishing up. You can pick up that branch to open your PR.