Extractor vals don't work in interpreter

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Aladdin: [http://scala-webapps.epfl.ch/bugtracking/bugs/displayItem.do?id=1295 bug 1295], [http://scala-webapps.epfl.ch/bugtracking/contribs/display.do?id=770 contrib 770]

== Code ==

class X { def unapply(v : Int) = Some(v + 1) }
val q = new X
5 match { case q(x) => x }

== What happened ==

java.lang.ClassCastException:  cannot be cast to 

== What expected ==

Prints 6. This works in the compiler, and works in the interpreter if I use an object rather than class + val.

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Imported From: https://issues.scala-lang.org/browse/SI-5?orig=1
Reporter: @michelou

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@odersky said:
Lex should have a look at this one.

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@lexspoon said:
It has something to do with unapply's when mixed with nested objects. The following code generates the same error with the stand-alone compiler:

object A1 {
 object A2 {
   class X { def unapply(v : Int) = Some(v + 1) }
 }
}

object B1 {
  object B2 {
    val q = new A1.A2.X
  }
}

object Test {
  def main(args: Array[String]) {
    import B1.B2.q
    val res = 5 match { case q(x) => x }
    println(res)
  }
}

I have committed a test case at test/pending/run/bugtr0005.scala.

I don't know who should be assigned pattern-matching bugs right now. Burak, is it you still, or should it be passed to someone else or to devteam?

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@lexspoon said:
I have renamed the regression test t0005.scala.

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@burakemir said:
t0005 compiles now, but gives a class cast exception at runtime. I think it is related to the "odd typing bug" contribution

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@burakemir said:
It was not related to the other bugs, here is the thing after typer...

[[syntax trees at end of typer]]// Scala source: t5.scala
package <empty> {
  final object A1 extends java.lang.Object with ScalaObject {
    def this(): object A1 = {
      A1.super.this();
      ()
    };
    final object A2 extends java.lang.Object with ScalaObject {
      def this(): object A1.this.A2 = {
        A2.super.this();
        ()
      };
      class X extends java.lang.Object with ScalaObject {
        def this(): A2.this.X = {
          X.super.this();
          ()
        };
        def unapply(v: Int): Some[Int] = scala.Some[Int](v.+(1))
      }
    }
  };
  final object B1 extends java.lang.Object with ScalaObject {
    def this(): object B1 = {
      B1.super.this();
      ()
    };
    final object B2 extends java.lang.Object with ScalaObject {
      def this(): object B1.this.B2 = {
        B2.super.this();
        ()
      };
      private[this] val q: A1.A2.X = new A1.A2.X();
      <stable> <accessor> def q: A1.A2.X = B2.this.q
    }
  };
  final object Test extends java.lang.Object with ScalaObject {
    def this(): object Test = {
      Test.super.this();
      ()
    };
    def main(args: Array[String]): Unit = {
      <empty>;
      val res: Int = 5 match {
        case A1.A2.q.unapply(<unapply-selector>) <unapply> ((x @ _)) => x
      };
      scala.this.Predef.println(res)
    }
  }
}

and after explicitouter

  final class Test extends java.lang.Object with ScalaObject {
    def this(): object Test = {
      Test.super.this();
      ()
    };
    def main(args: Array[java.lang.String]): Unit = {
      val res: Int = {
        <synthetic> val temp2: Some[Int] = A1.A2.q().unapply(5);
        if (true)
          temp2.get()
        else
          throw new MatchError(5)
      };
      scala.this.Predef.println(res)
    }

and erasure

  final class Test extends java.lang.Object with ScalaObject {
    def this(): object Test = {
      Test.super.this();
      ()
    };
    def main(args: Array[java.lang.String]): Unit = {
      val res: Int = {
        <synthetic> val temp2: Some = A1.A2.$$asInstanceOf[object B1#B2]().q().unapply(5);
        if (true)
          scala.Int.unbox(temp2.get())
        else
          throw new MatchError(scala.Int.box(5))
      };
      scala.this.Predef.println(scala.Int.box(res))
    }
  }

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@odersky said:
Milestone 2.6.1 deleted