Pattern matching in Dotty 0.24.0-RC1

1

//  x match {
//    case _: Box[Square] | _: Box[Circle] => ???
//  }

[info]         matchResult10[Nothing]: 
[info]           {
[info]             case val x13: Object = App.x()
[info]             matchAlts1[Unit]: 
[info]               {
[info]                 matchAlts2[Unit]: 
[info]                   {
[info]                     if x13.isInstanceOf[App.App$Box] then 
[info]                       return[matchAlts2] ()
[info]                      else ()
[info]                     if x13.isInstanceOf[App.App$Box] then 
[info]                       return[matchAlts2] ()
[info]                      else ()
[info]                     return[matchAlts1] ()
[info]                   }
[info]                 ???()
[info]               }
[info]             throw new MatchError(x13)
[info]           }

2

//  x match {
//    case _: (Box[Square] | Box[Circle]) => ???
//  }

[info]         matchResult10[Nothing]: 
[info]           {
[info]             case val x13: Object = App.x()
[info]             if 
[info]               x13.isInstanceOf[App.App$Box].||(
[info]                 x13.isInstanceOf[App.App$Box]
[info]               )
[info]              then 
[info]               {
[info]                 ???()
[info]               }
[info]              else ()
[info]             throw new MatchError(x13)
[info]           }