implicit.repl

> scala -Xlog-implicits
Welcome to Scala 2.12.6 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_172).
Type in expressions for evaluation. Or try :help.

scala> object A {
     |   import scala.language.implicitConversions
     |   implicit val int: Int = 1
     |   def a[A]: A = ???
     |   implicit def asString[A](implicit i: Int): Long => A = _ => a[A]
     |
     |   val s: String = 1L
     | }
<console>:17: asString is not a valid implicit value for Long(1L) => String because:
type mismatch;
 found   : Long(1L)
 required: Int
         val s: String = 1L
                         ^
<console>:17: error: type mismatch;
 found   : Long(1L)
 required: String
         val s: String = 1L
                         ^

scala> object B {
     |   import scala.language.implicitConversions
     |   implicit val int: Int = 1
     |   def a[A]: A = ???
     |   implicit def asString[A](l: Long)(implicit i: Int): A = a[A]
     |
     |   val s: String = 1L
     | }
defined object B