What is the Scala identifier “implicitly”?

implicitly is avaliable in Scala 2.8 and is defined in Predef as:

def implicitly[T](implicit e: T): T = e

It is commonly used to check if an implicit value of type T is available and return it if such is the case.

Simple example from retronym’s presentation:

scala> implicit val a = "test" // define an implicit value of type String
a: java.lang.String = test
scala> val b = implicitly[String] // search for an implicit value of type String and assign it to b
b: String = test
scala> val c = implicitly[Int] // search for an implicit value of type Int and assign it to c
<console>:6: error: could not find implicit value for parameter e: Int
       val c = implicitly[Int]
                         ^