Compilation errors when Error is inside submodule

[ludiazv]

Hi, I'm testing snafu and I'm trying to use it in submodule but I can't get it to compile. This is the test code:

mod error_module {
    pub use snafu::{ResultExt, Snafu};

    #[derive(Debug, Snafu)]
    pub enum Error {
        #[snafu(display("This is a test errror {}: {}", tests, source))]
        TestError {
            tests: String,
            source: std::io::Error,
        },
    }

    pub type Result<T, E = Error> = std::result::Result<T, E>;
}

use crate::error_module::*;
use std::fs;

fn test_error() -> Result<()> {
    let _ = fs::read("this will fail").context(TestError {
        tests: "some value".to_string(),
    })?;
    Ok(())
}

fn main() {
    println!("{:?}", test_error());
}

The output is the following:

error[E0422]: cannot find struct, variant or union type `TestError` in this scope
  --> src/main.rs:21:44
   |
21 |  let _=fs::read("this will fail").context( TestError { tests:"some value".to_string() })?;
   |                                            ^^^^^^^^^ not found in this scope
help: possible candidates are found in other modules, you can import them into scope
   |
16 | use crate::error_module::Error::TestError;
   |
16 | use crate::error_module::TestError;
   |

error: aborting due to previous error

Changing line with the error to:

let _=fs::read("this will fail").context( error_module::TestError { tests:"some value".to_string() })?;

I get this:

error[E0603]: struct `TestError` is private
  --> src/main.rs:21:58
   |
21 |  let _=fs::read("this will fail").context( error_module::TestError { tests:"some value".to_string() })?;
   |                                                          ^^^^^^^^^

error: aborting due to previous error

If I try this:

let _=fs::read("this will fail").context( error_module::Error::TestError { tests:"some value".to_string() })?;

I get:

   Compiling lua v0.1.0 (/home/ldiaz/experiments/rust/lua)
error[E0063]: missing field `source` in initializer of `error_module::Error`
  --> src/main.rs:21:44
   |
21 |  let _=fs::read("this will fail").context( error_module::Error::TestError { tests:"some value".to_string() })?;
   |                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `source`

error[E0277]: the trait bound `error_module::Error: snafu::IntoError<_>` is not satisfied
  --> src/main.rs:21:35
   |
21 |  let _=fs::read("this will fail").context( error_module::Error::TestError { tests:"some value".to_string() })?;
   |                                   ^^^^^^^ the trait `snafu::IntoError<_>` is not implemented for `error_module::Error`

error: aborting due to 2 previous errors

The code works fine if I remove the error_module What I'm doing wrong?. I'm using rust 2018, rustc 1.37 on linux.

Thanks

[shepmaster]

Does this section of the user's guide address your issue?

It looks like you need

#[derive(Debug, Snafu)]
#[snafu(visibility(pub(crate)))]
pub enum Error {

[shepmaster]

Opinion-wise, I don't think there's much benefit to placing your Error type in a module if you are going to be creating it from outside of that module.

[ludiazv]

Thanks!!!! It worked! I tried with visibility but somehow I wrote the directive wrong. I wnated to same same error across various module. It could an anti-pattern but for small programs will reduce the boilerplate and simplify error management at main program level as we have to deal with unique Result.

Thank you for your help.

[shepmaster]

I wnated to same same error across various module

That's fine, I'd just define the error type at the root of your hierarchy, instead of putting it in a module at all.