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 => {} } }