An annotation to be applied to a match expression. If present, the compiler will verify that the match has been compiled to atableswitch or lookupswitch and issue a warning if it instead compiles into a series of conditional expressions. Example usage:

val Constant = 'Q'def tokenMe(ch: Char) = (ch: @switch) match {  case ' ' | '\t' | '\n'  => 1  case 'A' | 'Z' | '$'    => 2  case '5' | Constant     => 3  // a non-literal may prevent switch generation: this would not compile  case _                  => 4}

Note: for pattern matches with one or two cases, the compiler generates jump instructions. Annotating such a match with@switch does not issue any warning.