Scala pattern match and logical not

Question

I have:

 x match { 
  case a: SomeType => doSomething()
  case _ => doSomethingElse()
 }

Is there a way to check that 'a' is NOT of a given type?

like so:

x match { 
  case !(a: SomeType) => doSomething()
  case _ => doSomethingElse()
}

Edit: I agree the question may not be very clear but my interest was mostly the logical not and it has been answered.

Answer 1

Something like this:

x match { 
  case a: if !a.isInstanceOf[MyFirst] => doSomething()
  case b: MySecond => doSomething()
  case _ => doSomethingElse()
}