Multiple constructor and implicit parameter

Question

I have some scala code

class A (a: Int, b:Int) (implicit typeinfo: TypeInformation[T]) {
  ...
}

but if i define a new constructor

class A (a: Int, b:Int) (implicit typeinfo: TypeInformation[T]) {
  def this(a: Int]) {
      this(a, 0)   
  }
  ...
}

the compiler throws "could not find implicit value for parameter" error. I tried this(a,0)(typeinfo) but got the same error

What could be the cause?

Gal Naor Gal Naor · Accepted Answer · 2019-10-17T06:10:45

The main constructor is the one when you defined at the class declaration

this is a secondary constructor and it's still a function, you need to define the implicit in the declaration.

if you do this:

class A (a: Int, b:Int) (implicit typeinfo: TypeInformation[T]) {
  def this(a: Int])(implicit typeinfo: TypeInformation[T]) {
      this(a, 0)   
  }
  ...
}

It will work.

Multiple constructor and implicit parameter

1 Answers