e1.scala

case class ScalaChan()

implicit def ScalaChanEqual: Equal[ScalaChan] = new Equal[ScalaChan] {
  def equal(a1: ScalaChan, a2: ScalaChan): Boolean = a1 == a2
}

implicit def ScalaChanEqual: Equal[ScalaChan] = equal(_ == _)

implicit def ScalaChanEqual: Equal[ScalaChan] = equalA

assert(ScalaChan() === ScalaChan())

e2.scala

scala> 1 === 1
res39: Boolean = true

scala> 1 /== 1
res41: Boolean = false

scala> 1 /== 1L
<console>:23: error: type mismatch;
 found   : Long(1L)
 required: Int
              1 /== 1L
                    ^

e3.scala

assert("Scalaz" ≟ "Scalaz")

assert("Scalaちゃん" ≠ "Scalaz")

e4.scala

scala> "Scalaz" assert_=== "Scalaz"

scala> "Scalaちゃん" assert_=== "Scalaz"
java.lang.RuntimeException: Scalaちゃん ≠ Scalaz
        at scalaz.Scalaz$.error_(Scalaz.scala:100)
        at scalaz.Identity$class.assert_$eq$eq$eq(Identity.scala:32)
        at scalaz.Identity$$anon$1.assert_$eq$eq$eq(Identity.scala:169)
        .
        .
        .
        .

scala> "Scalaちゃん" assert_≟ "Scalaちゃん"

i1.scala

val i: Identity[Int] = 1

val a: Int = i

i2.scala

"Scalaz" ?? "Scalaちゃん" assert_=== "Scalaz"

(null: String) ?? "Scalaちゃん" assert_=== "Scalaちゃん"

i3.scala

1 |> (_ + 1) assert_=== 2

1 |> Option.apply assert_=== Some(1)

i4.scala

1.some assert_=== Some(1)

1.right[String] assert_=== Right(1)

"Scalaちゃん".left[Int] assert_=== Left("Scalaちゃん")

"ゲソ".pair.assert_===(("ゲソ", "ゲソ"))

"ゲソ".pair assert_=== "ゲソ".squared

i5.scala

1.whileDo(_ + 1, _ < 10) assert_=== 10

"Scala".doWhile({ s => println(s); readLine }, _ != "Scalaz") assert_=== "Scalaz"