Scala compiler says unreachable code, why?

Posted by taotree on Stack Overflow See other posts from Stack Overflow or by taotree
Published on 2010-04-13T18:41:32Z Indexed on 2010/04/13 18:43 UTC
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scala

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unreachable-code

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error

I'm new to Scala... Here's the code:

  def ack2(m: BigInt, n: BigInt): BigInt = {
      val z = BigInt(0)
      (m,n) match {
          case (z,_) => n+1
          case (_,z) => ack2(m-1,1) // Compiler says unreachable code on the paren of ack2(
          case _ => ack2(m-1, ack2(m, n-1)) // Compiler says unreachable code on the paren of ack2(
      }
  }

I'm trying to understand that... why is it giving that error?

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