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 => {} } }