XO0429: invalid valued enum
An enum may declare a value type, Int or Str, as enum Level: Str { Debug = "debug" }. Every variant is then field-less, the enum takes no type parameters, and each value is a constant of the value type. A value on an enum that names no value type is this error too: write enum E: Int or : Str. See core 2.3.
Example
enum Level: Float { Low }Fix
enum Level: Int { Low }Run xo explain XO0429 for this text in a terminal, or see
section 10.6 of the specification.