How to mix-in a trait to instance?

Question

Given a trait MyTrait:

trait MyTrait {
  def doSomething = println(\"boo\")
}

it can be mixed into a class with extends<

Answer 1

Why not use Scala's extend my library pattern?

https://alvinalexander.com/scala/scala-2.10-implicit-class-example

I'm not sure what the return value is of:

var o = DBHelper.loadMyEntityFromDB(primaryKey);

but let us say, it is DBEntity for our example. You can take the class DBEntity and convert it to a class that extends your trait, MyTrait.

Something like:

trait MyTrait {
  def doSomething = {
    println("boo")
  }
}

class MyClass() extends MyTrait

// Have an implicit conversion to MyClass
implicit def dbEntityToMyClass(in: DBEntity): MyClass = 
new MyClass()

I believe you could also simplify this by just using an implicit class.

implicit class ConvertDBEntity(in: DBEntity) extends MyTrait

I particularly dislike the accepted answer here, b/c it overloads the :: operator to mix-in a trait.

In Scala, the :: operator is used for sequences, i.e.:

val x = 1 :: 2 :: 3 :: Nil

Using it as a means of inheritance feels, IMHO, a little awkward.