This hangs the Scala compiler (tried 2.11.8 and 2.12.1)

converter.scala

import shapeless.{:+:, CNil, Coproduct, HList, LabelledGeneric}
import shapeless.ops.hlist.{Align, Intersection}

/**
 * Allows you to convert between case classes which have compatible generic representations
 * i.e. Foo(bar: String) is convertable to Baz(bar: String) due to the field names & types being the same
 */
trait Converter[A, B] {
  def convert(a: A): B
}

object Converter {

  implicit class ConverterOps[A](a: A) {
    def convert[B](implicit c: Converter[A, B]) = c.convert(a)
  }

  implicit def coproductConvert[H, T <: Coproduct, B](
    implicit
    h: Converter[H, B],
    c: Converter[T, B]
  ) = new Converter[H :+: T, B] {
    override def convert(a: :+:[H, T]) = a.eliminate(h.convert, c.convert)
  }

  implicit def cnilConvert[B] = new Converter[CNil, B] {
    override def convert(a: CNil) = throw new Exception("Impossible")
  }

  implicit def convert[A, R1 <: HList, B, R2 <: HList, I <: HList](
    implicit
    l1: LabelledGeneric.Aux[A, R1],
    l2: LabelledGeneric.Aux[B, R2],
    s: Intersection.Aux[R1, R2, I],
    e: Align[I, R2]
  ) = new Converter[A, B] {
    override def convert(a: A) = {
      l2.from(e(s(l1.to(a))))
    }
  }
}

Turns out it is the use of Intersection causing the hang