Parsing a string into multiple types

Using Swift
7

I believe it’s because the case evaluation has to return a Bool i.e case foo and case foo where foo.bar evaluates to a true/false value which is used to decide whether the match is successful or not. I suppose an optional binding (where let a = b) could be supported by treating it as a Bool, however if you really want to do optional binding, the only way to do it now would be inside the case statement:

// For convenience.
func other() -> Self {
  return .other(type: type, value: value)
}

switch type {
  case “validUntil”: 
    if let value = parseDate(value) {
      self = .validUntil(value)
    } else {
      self = other()
    }
  ...
}