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error enum

An enum with one variant per way an operation can fail.

An error enum lists the failures a caller can tell apart and act on, each variant carrying the data that failure needs.

Examples

  • enum ConfigError { MissingEquals { line: usize }, UnknownKey { line: usize, key: String } } lets a caller match on which failure happened and read its line number.

See also

Error trait thiserror non_exhaustive enum
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