RustRun use cases are unclear, leading to unexpected errors

[dmitriyl]

https://gist.github.com/dmitry-smith/5f72970e84b38ed38db2

:RustRun does not work for me. It always shows the same error:
main.rs:9:25: 9:41 error: unresolved name rand::thread_rng
main.rs:9 let secret_number = rand::thread_rng().gen_range(1, 101);
^~~~~~~~~~~~~~~~
error: aborting due to previous error

But when I try to do the same from a command line with "Cargo run" everything is ok. What can I do to fix it? Thx.

[habamax]

I have the same issue. It could be that RustRun uses rustc to compile and then run executable.
I think RustRun should use Cargo run first and rustc as a fallback.

[habamax]

It looks like we can have

autocmd BufRead,BufNewFile Cargo.toml,Cargo.lock,*.rs compiler cargo

in vimrc and be able to :make run to issue Cargo run.

[jfelchner]

If cargo is the blessed way by the Rust community for Rust to be compiled in the 99% case, I think it should be the thing that's executed when RustRun is called. Or at the very least check to see if the cargo executable exists. If it does, use that, if not, use rustc.

[jdhoek]

Is there a known workaround for this issue?

[davidmwalton]

I believe I'm seeing the same (or a closely related) issue. Compiling my app with cargo run causes no issue, but the syntax checking within Vim throws: unresolved name rand::thread_rng

Seconding jdhoek's question about whether or not there is a workaround.

Can we possibly squelch known bad errors or something like this? Or otherwise configure rust.vim to use cargo the compile checker vs. rustc?

[da-x]

RustRun is a meant as an low-level (and old) way to run Rust code. I will be changing the documentation more to stress that out. Will keep this open in the meanwhile.

[heyrict]

I'm currently use the 2018 edition and RustRun does not read the [dependency] section in Cargo.toml and will get me a E0463: cannot find crate error.

Currently I'm using a simple command as a replacement. Hope there would be a :CargoRun command in the future.

command -nargs=* RustRun up | execute "!cargo run" <q-args>

[sandmuel]

Currently I'm using a simple command as a replacement. Hope there would be a :CargoRun command in the future.

Is :CargoRun a command yet?