| An undeclared crate, module, or type was used. | |
| Erroneous code example: | |
| ```compile_fail,E0433 | |
| 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: | |
| ``` | |
| 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: | |
| ```compile_fail | |
| 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. |