class constructor with implicit parameters

scala

implicit parameter list

  1. Implicit applies to the whole list of arguments after it. Normal parameters and implicit parameters cannot be mixed in a single parameter list.
  2. A method can only have one implicit parameter list and the list has to be the last one.
  3. Auxiliary constructor must have a non-implicit parameter list.
// error, cannot mix non-implicit and implicit together
class Test1(a: Int, implicit b: Int)

// correct, implicit list is the last list
class Test2(a: Int)(implicit b: Int)

// correct, mix with non-implicit with implicit val
// implicit actually is defined on the b() method
class Test3(a: Int, implicit val b: Int)

class Test4(a: Int)(implicit b: Int) {
	// error, auxiliary constructor must have one non-implicit parameter
  def this(implicit b: Int) {
    this(3)(b) 
  }
}

class Test5(a: Int)(implicit b: Int) {
// correct, auxiliary constructor with an empty non-implicit parameter
  def this()(implicit b: Int) {
    this(3)(b)
  }
}
Support me