== Why is this an issue?

Importing every public name from a module using a wildcard (``++use _::*++``) is a bad idea because:

* It could lead to conflicts between names defined locally and the ones imported.
* It reduces code readability as developers will have a hard time knowing where names come from.
* It clutters the local namespace, which makes debugging more difficult.

Remember that imported names can change when you update your dependencies. A wildcard import that works today might be broken tomorrow.

=== Exceptions

No issue will be raised for modules that their name contains ``++prelude ++``. Many crates, including the standard library, provide modules named ``++prelude ++`` that are specifically designed for wildcard import.

No issue will be raised in test modules. This is defined as any module with ``++test++`` in the name.

== How to fix it

There are two ways to avoid a wildcard import:

* Replace it with `use mymodule;` and access module members as `mymodule::myfunction`. If the module name is too long, alias it to a shorter name. Example: `use std::collections as col;`
* List every imported name. If necessary, import statements can be split on multiple lines using parentheses (preferred solution) or backslashes.

=== Code examples

==== Noncompliant code example

[source,rust]
----
use std::collections::*; // Noncompliant
fn main() {
    let mut map = HashMap::new();
    map.insert(1, 2);
}
----

==== Compliant solution

[source,rust]
----
use std::collections::HashMap;
fn main() {
    let mut map = HashMap::new();
    map.insert(1, 2);
}
----
Or

[source,rust]
----
use std::collections::HashMap as HM;
fn main() {
    let mut map = HM::new();
    map.insert(1, 2);
}
----

== Resources

=== Documentation

* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_imports