When trying to compile this with Scala 2.12.1 I got a NullPointerException

exception

☭ scala foo.scala 
cat: /release: No such file or directory
java.lang.NullPointerException
	at Main$Monad.<init>(foo.scala:29)
	at Main$$anon$1.<init>(foo.scala:58)
	at Main$.<init>(foo.scala:58)
	at Main$.<clinit>(foo.scala)
	at Main.main(foo.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at scala.reflect.internal.util.ScalaClassLoader.$anonfun$run$2(ScalaClassLoader.scala:98)
	at scala.reflect.internal.util.ScalaClassLoader.asContext(ScalaClassLoader.scala:32)
	at scala.reflect.internal.util.ScalaClassLoader.asContext$(ScalaClassLoader.scala:30)
	at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.asContext(ScalaClassLoader.scala:129)
	at scala.reflect.internal.util.ScalaClassLoader.run(ScalaClassLoader.scala:98)
	at scala.reflect.internal.util.ScalaClassLoader.run$(ScalaClassLoader.scala:90)
	at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:129)
	at scala.tools.nsc.CommonRunner.run(ObjectRunner.scala:22)
	at scala.tools.nsc.CommonRunner.run$(ObjectRunner.scala:21)
	at scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:39)
	at scala.tools.nsc.CommonRunner.runAndCatch(ObjectRunner.scala:29)
	at scala.tools.nsc.CommonRunner.runAndCatch$(ObjectRunner.scala:28)
	at scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:39)
	at scala.tools.nsc.ScriptRunner.runCompiled(ScriptRunner.scala:170)
	at scala.tools.nsc.ScriptRunner.$anonfun$runScript$1(ScriptRunner.scala:187)
	at scala.tools.nsc.ScriptRunner.$anonfun$runScript$1$adapted(ScriptRunner.scala:187)
	at scala.tools.nsc.ScriptRunner.$anonfun$withCompiledScript$2(ScriptRunner.scala:156)
	at scala.tools.nsc.ScriptRunner.runScript(ScriptRunner.scala:124)
	at scala.tools.nsc.ScriptRunner.runScriptAndCatch(ScriptRunner.scala:200)
	at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:63)
	at scala.tools.nsc.MainGenericRunner.run$1(MainGenericRunner.scala:88)
	at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:99)
	at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:104)
	at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)

null.scala

import scala.language.higherKinds

object jazz {

  trait Functor[F[_]] {
    def map[A,B](value: F[A])(func: A => B): F[B]
  }

  abstract class Applicative[F[_]](implicit val functor: Functor[F]) extends Functor[F] {
    def pure[A](a: A): F[A]

    def ap[A,B](value: F[A])(func: F[A => B]): F[B]

    def map[A,B](value: F[A])(func: A => B): F[B] = functor.map[A,B](value)(func)
  }

  abstract class Monad[F[_]](implicit val applicative: Applicative[F]) extends Applicative[F]()(applicative.functor) {
    def flatMap[A,B](value: F[A])(func: A => F[B]): F[B]

    def pure[A](a: A): F[A] = applicative.pure[A](a)
    def ap[A,B](value: F[A])(func: F[A => B]): F[B] = applicative.ap[A,B](value)(func)

  }

  implicit val optionFunctor: Functor[Option] = new Functor[Option] {
    def map[A,B](value: Option[A])(func: A => B): Option[B] = {
      value match {
        case None => None
        case Some(a) => Some(func(a))
      }
    }
  }

  implicit val optionApplicative: Applicative[Option] = new Applicative[Option] {

    def pure[A](a: A): Option[A] = Some(a)

    def ap[A,B](value: Option[A])(func: Option[A => B]): Option[B] = {
      func match {
        case None => None
        case Some(f) => functor.map(value)(f)
      }
    }
  }

  /**
   * This will compile fine if instead we use:
   *    implicit val optionMonad: Monad[Option] = new Monad[Option]()(optionApplicative) {
   */
  implicit val optionMonad: Monad[Option] = new Monad[Option] {
    def flatMap[A,B](value: Option[A])(func: A => Option[B]): Option[B] = {
      value match {
        case None => None
        case Some(a) => func(a)
      }
    }
  }

  def main(args: Array[String]): Unit = {
    println("hello, friend")
  }


}