Struct in module, used in another module : E0308

help
1

I am trying to learn Rust but it is fighting me every step of the way. I have the following code (in a module called events.rs):

let search : softtube::Search = match text.len() {
                0 => softtube::Search::Limit(-1),
                _ => softtube::Search::Text(text)
            };
app.videos.search(Some(search));  <-- Error occurs here!!

Search is defined in a module called softtube.rs:

#[derive(Debug, PartialEq, Eq, Clone)]
pub enum Search {
    Limit(i32),
    Text(String)
}

And now I am getting the error :

events::softtube::Search
let search : softtube::Search = match text.len() { ... }
mismatched types

expected enum `softtube::Search`, found enum `events::softtube::Search`

note: expected type `softtube::Search`
found type `events::softtube::Search`rustc(E0308)

So it says on the second row of the error message that search is of the type softtube::Search, but later, on the last row it says it is the type events::softtube::Search!?! Why Rust? Why are you punishing me?

The first couple of weeks I wrote all Rust code in main.rs just to avoid crap like this, but now I have to bite the bullet and finally learn how to do this. So can anyone help me with this? Please?

2

Do you have Search defined multiple times in different modules?

3

No, but I do have a couple of lower case functions and variables named 'search', can that cause this problem?

4

Like @RustyYato, I can just guess. It's better if you can provide minimal code that can compile that produce the same error. When trying to reproduce with a minimal code, I tend to find the problem myself. This may help some how?

1 Like
5

@limira, I will try that, but in my case they are actually different files. Doesn't that matter?

I link them in with this syntax (for some reason I don't need the #[path="path"] in main.rs):

#[path="softtube.rs"]
mod softtube;

6

No, you just do this:

// in main.rs
mod mod1; // and a file `./mod1.rs` or `./mod1/mod.rs`
mod mod2;
mod mod3;
7

If I don't use the path-syntax (in files other than main.rs), I get this error:

src/misc.rs
file not found for module `misc`
help: name the file either events/misc.rs or events/misc/mod.rs inside the directory "src"rustc(E0583)
8

But good news, my problem seemed to be the missing 'crate::' in front of softtube::Search() that you used in the playground example! Thanks for that!

I can't figure out how to make the playground link, but I just needed to add the crate::...

9

I think you place your files in wrong folders/directories. If they are all in their correct directories, you don't have to #[path="softtube.rs"] (In fact, this the first time I see it).

If you want to avoid the crate::, bring it into scope by using use ...;

use some::path::to::EnumItem;
let item = EnumItem::Variant;
10

Well, I created a project with 'cargo new' and then place all my files inside the src folder, isn't that correct?

So basically

src/

  • main.rs
  • events.rs
  • softtube.rs
  • ....

cargo.toml
...

11

If every mod are in main.rs:

// main.rs
mod mod1;

You have two options for the file (that contains code for your mod1):

src/mod1.rs
// or 
src/mod1/mod.rs

But if you want a mod2 in module mod1:

// in mod1.rs (or mod1/mod.rs)
mod mod2;

You have to place the file in:

src/mod1/mod2.rs //(The file is in folder: src/mod1)
// or
src/mod1/mod2/mod.rs
2 Likes
12

I am confident that I have completely misunderstood a whole lot of things, but anyway here are my code simplified a lot : https://github.com/Hultan/softtube-error

  1. Go to events.rs and comment out '#[path="softtube.rs"]' and you will get the module error I talked about.
src/misc.rs
file not found for module `misc`
help: name the file either events/misc.rs or events/misc/mod.rs inside the directory "src"rustc(E0583)
  1. Go to events.rs and remove the three 'crate::' and you will get the error message I originally asked about. But it works with the 'crate::' so I am happy with that for now, but just in case you wanted to see exactly how I have messed this up :slight_smile:

About my use of the 'mod' keyword in main.rs and events.rs, I have a suspicion that I am using that very wrong. The only thing I am trying to achieve here at this moment is to not have all the code in one file (main.rs). I am not trying to build a "library" (cargo new --lib) or anything...

13

A few YouTube-videos later and I realized that you can write :

use crate::module;

and

use super::module;

That makes things easier... :slight_smile:

I prefer to learn things by doing, until I go completely mad, and then I do what I should have done from the beginning. Read the manual, and learn from others...

Thanks everybody who helped me...

14

Yeah, I understand that. But I think read The Book first is a good idea. It helps me very much.

15

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