title: Shapeless could not find implicits
body: <p>I'm trying to generate objects via <code>shapeless</code>
  With this code snippet:</p>
  
  <pre><code>import shapeless._
  case class T1(i: Int, v: String)
  
  class WorkbenchSpec extends FlatSpec with Matchers {
    "Gen tests" should "do smth interesting" in {
      println(ObjectGenerators.gen(classOf[T1]))
    }
  }
  
  object FieldGen extends Poly0 {
    implicit val genInt = at[Int](0)
    implicit val genString = at[String]("")
  }
  
  object ObjectGenerators {
  
    def gen[T, TRepr &lt;: HList](c: Class[T])
                              (implicit
                               gen: Generic.Aux[T, TRepr],
                               fill: ops.hlist.FillWith[FieldGen.type, TRepr]
                              ): T = {
  
      gen.from(HList.fillWith[TRepr](FieldGen))
    }
  
    def fillList[T &lt;: HList](implicit fill: ops.hlist.FillWith[FieldGen.type, T]) =
      fill()
  }
  </code></pre>
  
  <p>I get an error:</p>
  
  <blockquote>
    <p>could not find implicit value for parameter fillWith:
    shapeless.ops.hlist.FillWith[com.media.gr.core.ObjectGenerators.FieldGen.type,gen.Repr]
        gen.from(HList.fillWithgen.Repr)</p>
  </blockquote>
  
  <p>But in <code>sbt</code> console if I do:</p>
  
  <pre><code>case class T1(i: Int, v: String)
  object FieldGen extends Poly0 {
    implicit val genInt = at[Int](0)
    implicit val genString = at[String]("")
  }
  def gen[T, TRepr &lt;: HList](c: Class[T])
                              (implicit
                               gen: Generic.Aux[T, TRepr],
                               fill: ops.hlist.FillWith[FieldGen.type, TRepr]
                              ): T = {
  
      gen.from(HList.fillWith[TRepr](FieldGen))
    }
  </code></pre>
  
  <p>I get generated result. What am i doing wrong?</p>