object Encoder {
  implicit def apply[R <: Product]: Encoder[R] = macro applyImpl[R]
  def applyImpl[R: c.WeakTypeTag](c: blackbox.Context): c.Expr[Encoder[R]] = {
    import c.universe._
    c.Expr[Encoder[R]](q"""
      new ${weakTypeOf[Encoder[R]]} {
        override def encode(r: ${weakTypeOf[R]}): Array[Byte] =
          implicitly[_root_.Serializer[${weakTypeOf[R]}]].serialize(r)
        }
    """)
  }
}

case class Record(i: Int)

object Serializers {
  implicit def recordSerializer: Serializer[Record] =
    (r: Record) => Array.emptyByteArray
}

import Serializers._

class Processor extends BaseProcessor[Record]

// [error] Loader.scala:10:22: could not find implicit value for parameter e: Serializer[Record]
// [error] class Processor extends BaseProcessor[Record]
// [error]                         ^
// [error] one error found

object x {
  import Serializers._ // moving the import here also makes it NOT compile
  class Processor extends BaseProcessor[Record]
}