Error code E0433

An undeclared crate, module, or type was used.

Erroneous code example:

#![allow(unused)]
fn main() {
let map = HashMap::new();
// error: failed to resolve: use of undeclared type `HashMap`
}

Please verify you didn’t misspell the type/module’s name or that you didn’t forget to import it:

#![allow(unused)]
fn main() {
use std::collections::HashMap; // HashMap has been imported.
let map: HashMap<u32, u32> = HashMap::new(); // So it can be used!
}

If you’ve expected to use a crate name:

#![allow(unused)]
fn main() {
use ferris_wheel::BigO;
// error: failed to resolve: use of undeclared module or unlinked crate
}

Make sure the crate has been added as a dependency in Cargo.toml.

To use a module from your current crate, add the crate:: prefix to the path.