Error code E0170

A pattern binding is using the same name as one of the variants of a type.

Erroneous code example:

enum Method {
    GET,
    POST,
}

fn is_empty(s: Method) -> bool {
    match s {
        GET => true,
        _ => false
    }
}

fn main() {}

Run

Enum variants are qualified by default. For example, given this type:

enum Method {
    GET,
    POST,
}

Run

You would match it using:

enum Method {
    GET,
    POST,
}

let m = Method::GET;

match m {
    Method::GET => {},
    Method::POST => {},
}

Run

If you don’t qualify the names, the code will bind new variables named “GET” and “POST” instead. This behavior is likely not what you want, so rustc warns when that happens.

Qualified names are good practice, and most code works well with them. But if you prefer them unqualified, you can import the variants into scope:

use Method::*;
enum Method { GET, POST }

Run

If you want others to be able to import variants from your module directly, use pub use:

pub use Method::*;
pub enum Method { GET, POST }

Run

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