Why can't the first parameter list of a class be implicit?

Question

scala> class A(implicit a: Int);
defined class A

scala> class B()(implicit a: Int);
defined class B

scala> new A()(1)
res1: A = A@159d450

scala> new B         


        

Answer 1

The way I see it is that implicit parameter list does not replace the regular one(s). Since for constructor definitions at least one parameter list is needed, if nothing is indicated explicitly '()' is generated.

While this might be indeed puzzling, it's in line with generating an empty constructor when no parameter lists at all are present.