t6048.scala:3: error: unreachable code
    case _ if false => x // unreachable
                       ^
t6048.scala:8: error: unreachable code
    case _ if false => x // unreachable
                       ^
t6048.scala:13: error: patterns after a variable pattern cannot match (SLS 8.1.1)
    case _ => x
         ^
t6048.scala:14: error: unreachable code due to variable pattern on line 13
    case 5 if true  => x // unreachable
                       ^
four errors found