Error code E0530

A binding shadowed something it shouldn’t.

A match arm or a variable has a name that is already used by something else, e.g.

• struct name
• enum variant
• static
• associated constant

This error may also happen when an enum variant with fields is used in a pattern, but without its fields.

#![allow(unused)]
fn main() {
enum Enum {
    WithField(i32)
}

use Enum::*;
match WithField(1) {
    WithField => {} // error: missing (_)
}
}

Match bindings cannot shadow statics:

#![allow(unused)]
fn main() {
static TEST: i32 = 0;

let r = 123;
match r {
    TEST => {} // error: name of a static
}
}

Fixed examples:

#![allow(unused)]
fn main() {
static TEST: i32 = 0;

let r = 123;
match r {
    some_value => {} // ok!
}
}

or

#![allow(unused)]
fn main() {
const TEST: i32 = 0; // const, not static

let r = 123;
match r {
    TEST => {} // const is ok!
    other_values => {}
}
}