Failed to resolve undeclared crate/module

help
1

Hello, all!

I have been using rust for a little while, and I've gotten this error many times before, but not like this. I am declaring a pub struct in a pub module, and even when I do not use it anywhere else in my project, I am getting this lint/compile error:

error[E0433]: failed to resolve: use of undeclared crate or module `date_time_utc_forms`
  --> domain/src/utils/date_time_utc_form.rs:13:12
   |
13 | pub struct DateTimeUtcForm {
   |            ^^^^^^^^^^^^^^^ use of undeclared crate or module `date_time_utc_forms`

The tree structure for this project is as follows (removed unrelated directories):

.
├── Cargo.lock
├── Cargo.toml
├── Dockerfile
├── rocket.toml
├── api
│   ├── Cargo.toml
│   └── src
│       ├── bin
│       │   └── main.rs
│       ├── lib.rs
│       └── post_handler.rs
├── domain
│   ├── Cargo.toml
│   └── src
│       ├── lib.rs
│       ├── models
│       │   ├── mod.rs
│       │   ├── photo.rs
│       │   └── post.rs
│       ├── schema.rs
│       └── utils
│           ├── date_time_utc_form.rs
│           └── mod.rs

I am trying to use this DateTimeUtcForm struct in my api crate, and it imports successfully there, which is weird, because why then am I getting that error? Even when I don't use it in api I still have the compile and lint errors. One thing I've notices is that it is calling the module date_time_utc_forms with an 's', even though I do not declare it with an 's' or import it with an 's' anywhere.

Here is my DateTimeUtcForm struct:

#[derive(Queryable, Insertable, Selectable, Serialize, Deserialize, Ord, Eq, PartialEq, PartialOrd, Debug)]
pub struct DateTimeUtcForm {
    pub time_taken: DateTime<Utc>,
}

I've noticed when I take off the Insertable and Selectable derives the issue seems to go away, so is this an issue with Diesel? I am using Diesel as an ORM, and the time_taken row on my diesel tables are of type Timestamptz. I feel like I have tried everything and read every StackOverflow post there is to read about this error, but I still have no luck. If you'd like to look at the full codebase, it's here. Any help or insight would be greatly appreciated! Thank you!

2

I haven't used diesel in pretty much forever, but I suspect it is causing the error, too. From the #[derive(Selectable)] docs (my emphasis):

To implement Selectable this derive needs to know the corresponding table type. By default, it uses the snake_case type name with an added s. It is possible to change this default by using #[diesel(table_name = something)].

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