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Scala command skips main if class is outside of singleton

EDIT: The main method that is not called in the Scala script is related (in particular, Rigi Jean-Gilles answer). This post provides more details to describe the problem. And the answer (by suish) gives a more practical demonstration to explain the behavior of the Scala team.

Content MiniScalaApp.scala

object MiniScalaApp {
  def main(args: Array[String]) = {
    println(s"Scala Version: ${scala.util.Properties.scalaPropOrElse("version.number", "unknown")}")
    println(new Dinosaur("Tyrannotitan", 4900))
    println(new Dinosaur("Animantarx ", 300))
  }

  class Dinosaur (name:String, weightKG: Int) {
    override def toString = f"$name, Weight: $weightKG kg"
  }
}

It is executed on the command line:

$ scala /myProject/src/main/scala/MiniScalaApp.scala

Produces the expected output:

Scala Version: 2.11.7
Tiranotitan, Weight: 4900 kg
Animantarx, Weight: 300 kg

However, if the Dinosaur class is located outside the single-element MiniScalaApp object, then the Scala command does not display console output, and an error message does not appear.

object MiniScalaApp {
  def main(args: Array[String]) = {
    println(s"Scala Version: ${scala.util.Properties.scalaPropOrElse("version.number", "unknown")}")
    println(new Dinosaur("Tyrannotitan", 4900))
    println(new Dinosaur("Animantarx ", 300))
  }
}

class Dinosaur (name:String, weightKG: Int) {
  override def toString = f"$name, Weight: $weightKG kg"
}

, , , MiniScalaApp.class

$ scalac /myProject/src/main/scala/MiniScalaApp.scala
$ scala MiniScalaApp

: , Scala -?

+4
2

scala -help .

scala script, ( ) . . scala .

, , script. - , , ...

scala> :paste
// Entering paste mode (ctrl-D to finish)

object MiniScalaApp {
  def main(args: Array[String]) = {
    println(s"Scala Version: ${scala.util.Properties.scalaPropOrElse("version.number", "unknown")}")
    println(new Dinosaur("Tyrannotitan", 4900))
    println(new Dinosaur("Animantarx ", 300))
  }
}

class Dinosaur (name:String, weightKG: Int) {
  override def toString = f"$name, Weight: $weightKG kg"
}

// Exiting paste mode, now interpreting.

defined object MiniScalaApp
defined class Dinosaur

define.so .

MiniScalaApp.main(Array())

, object Foo extends App , . def main .

+1

, main, / :

object MiniScalaApp {
  def main(args: Array[String]) = {
    println(s"Scala Version: ${scala.util.Properties.scalaPropOrElse("version.number", "unknown")}")
    println(new Dinosaur("Tyrannotitan", 4900))
    println(new Dinosaur("Animantarx ", 300))
  }
}

class Dinosaur (name:String, weightKG: Int) {
  override def toString = f"$name, Weight: $weightKG kg"
}

MiniScalaApp.main(args);

: Scala script

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