Strings in Switch Statements: ‘String’ does not conform to protocol ‘IntervalType’

This error is shown when an optional is used in a switch statement.
Simply unwrap the variable and everything should work.

switch opts["type"]! {
  case "abc":
    println("Type is abc")
  case "def":
    println("Type is def")
  default:
    println("Type is something else")
}

Edit:
In case you don’t want to do a forced unwrapping of the optional, you can use guard. Reference: Control Flow: Early Exit