so.scala

> shapeless-examples/console
[warn] Credentials file /home/folone/.ivy2/.credentials does not exist
[warn] Binary version (2.10) for dependency org.scala-lang#scala-library;2.10.2
[warn] 	in com.chuusai#shapeless_2.10.2;2.0.0-SNAPSHOT differs from Scala binary version in project (2.10.2).
[warn] Binary version (2.10) for dependency org.scala-lang#scala-compiler;2.10.2
[warn] 	in com.chuusai#shapeless_2.10.2;2.0.0-SNAPSHOT differs from Scala binary version in project (2.10.2).
[info] Starting scala interpreter...
[info] 
Welcome to Scala version 2.10.2 (OpenJDK 64-Bit Server VM, Java 1.7.0_40).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import shapeless._
import shapeless._

scala> import nat._
import nat._

scala> import examples.FactorialExamples.Factorial._
import examples.FactorialExamples.Factorial._

scala> factorial(5)
res0: shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[...]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]...

scala> toInt(res0)
res1: Int = 120

scala> factorial(6)
res2: shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[shapeless.Succ[...]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]]...

scala> toInt(res2)
error: 
     while compiling: <console>
        during phase: typer
     library version: version 2.10.2
    compiler version: version 2.10.2
  reconstructed args: -language:higherKinds -language:implicitConversions -deprecation -feature -bootclasspath /usr/lib/jvm/java-7-openjdk/jre/lib/resources.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/rt.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/sunrsasign.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/jsse.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/jce.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/charsets.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/netx.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/plugin.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/rhino.jar:/usr/lib/jvm/java-7-openjdk/jre/lib/jfr.jar:/usr/lib/jvm/java-7-openjdk/jre/classes:/home/folone/.sbt/boot/scala-2.10.2/lib/scala-library.jar -unchecked -Yrepl-sync -classpath /home/folone/workspace/shapeless/examples/target/scala-2.10.2/classes:/home/folone/workspace/shapeless/core/target/scala-2.10.2/classes:/home/folone/.sbt/boot/scala-2.10.2/lib/scala-compiler.jar:/home/folone/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.10.2.jar:/home/folone/.sbt/boot/scala-2.10.2/lib/scala-compiler.jar:/home/folone/.sbt/boot/scala-2.10.2/lib/jansi.jar:/home/folone/.sbt/boot/scala-2.10.2/lib/jline.jar:/home/folone/.sbt/boot/scala-2.10.2/lib/scala-reflect.jar

  last tree to typer: Select(This(package shapeless), ToInt)
              symbol: object ToInt in package shapeless (flags: <module> <triedcooking>)
   symbol definition: object ToInt
                 tpe: shapeless.ToInt.type
       symbol owners: object ToInt -> package shapeless
      context owners: value res3 -> object $iw -> object $iw -> object $iw -> object $iw -> object $iw -> object $iw -> object $iw -> object $iw -> object $read -> package $line24

== Enclosing template or block ==

Template( // val <local $iw>: <notype>
  "java.lang.Object" // parents
  ValDef(
    private
    "_"
    <tpt>
    <empty>
  )
  // 2 statements
  DefDef( // def <init>: <?>
    <method>
    "<init>"
    []
    List(Nil)
    <tpt>
    Block(
      Apply(
        super."<init>"
        Nil
      )
      ()
    )
  )
  ValDef( // private[this] val res3: <?>
    private <local>
    "res3"
    <tpt>
    Apply(
      "toInt"
      "res2"
    )
  )
)

== Expanded type of tree ==

SingleType(pre = ThisType(package shapeless), object ToInt)

uncaught exception during compilation: java.lang.StackOverflowError
java.lang.StackOverflowError
	at scala.tools.nsc.typechecker.Implicits$ImplicitSearch$$anonfun$8.apply(Implicits.scala:402)
	at scala.tools.nsc.typechecker.Implicits$ImplicitSearch$$anonfun$8.apply(Implicits.scala:402)
	at scala.reflect.internal.Types$FilterTypeCollector.traverse(Types.scala:4966)
	at scala.reflect.internal.Types$TypeTraverser.apply(Types.scala:4342)
	at scala.reflect.internal.Types$TypeTraverser.apply(Types.scala:4340)
	at scala.collection.immutable.List.loop$1(List.scala:170)
	at scala.collection.immutable.List.mapConserve(List.scala:186)
	at scala.reflect.internal.Types$TypeMap.mapOver(Types.scala:4176)
        ...
        at scala.reflect.internal.Types$FilterTypeCollector.traverse(Types.scala:4967)
	at scala.reflect.internal.Types$TypeTraverser.apply(Types.scala:4342)

That entry seems to have slain the compiler.  Shall I replay
your session? I can re-run each line except the last one.
[y/n]
Abandoning crashed session.