E0057

Constructor pattern expect payload.

The warning is emitted when the payload part is missing from the constructor pattern.

错误示例

///|
pub fn[T] is_some(s : T?) -> Bool {
  match s {
    Some => true
    None => false
  }
}

建议

Use (_) to ignore all the payloads.

///|
pub fn[T] is_some(s : T?) -> Bool {
  match s {
    Some(_) => true
    None => false
  }
}