Seq pattern match does not work in action

[Centaur]

Compile fails with message:
Error:scalac: unexpected UnApply collection.this.Seq.unapplySeq[String](<unapply-selector>) <unapply> ((single @ _))

import org.parboiled2.{Rule1, CharPredicate, ParserInput, Parser}

class SeqMatch(val input: ParserInput) extends Parser {
  def id: Rule1[String] = rule {
    capture(CharPredicate.Printable -- '.')
  }

  def root = rule {
    (id + '.') ~> {
      (ids: Seq[String]) =>
        ids match {
          case Seq(single) => MATCH
          case _ => MISMATCH
        }
    }
  }
}

[alexander-myltsev]

Pretty weird syntax: (id + '.'). What did you try to say?

For parser:

  object Parser extends SimpleParser {
    def id: Rule1[String] = rule {
      capture(CharPredicate.Printable -- '.')
    }

    def InputLine = rule {
      (id.+ ~ ch('.'))  ~> ((ids: Seq[String]) => ids match {
          case Seq(single) => MATCH
          case _ => MISMATCH
        }
      )
    }
  }

really weird code is generated:

// ... cut
            if (l)
              {
                val start = __psi.cursor;
                try {
                  val ids = __psi.valueStack.pop().asInstanceOf[scala.collection.immutable.Seq[String]];
                  ids match {
                    case collection.this.Seq.unapplySeq[String](<unapply-selector>) <unapply> ((single @ _)) => true
                    case _ => try {
                      __psi.registerMismatch()
                    } catch {
                      case _root_.org.parboiled2.ParserStateImpl.StartTracingException => __psi.bubbleUp(RuleTrace.MISMATCH)
                    }
                  }
                } catch {
                  case (e @ (_: _root_.org.parboiled2.ParserStateImpl[(_ @ <empty>)]#TracingBubbleException)) => e.bubbleUp(RuleTrace.Action, start)
                }
              }
            else
              false
// ... cut

@sirthias, have you seen this before?

[Centaur]

id + '.' means oneOrMore(id).separatedBy('.') but that is not the point. I just try to give a simplified code to get a Seq for matching.

[Jasper-M]

I ran into the same issue, with the following (not self contained, sorry) code:

def DayValue = rule { "Day" ~ "(" ~ 3.times(Integer).separatedBy(OptWhitespace ~ ",") ~ str(")") ~> {
  (nrs: Seq[Long]) => 
    val Seq(year, month, day) = nrs map {_.toInt}
    Day(year, month, day)
} }

It worked in Scala 2.10.4. Then I bumped versions to 2.11.7 and this issue appeared (among others).
I fixed it by indexing into the Seq instead.