SIP-71: How will implicit convertion to scala.Boolean be implemented?

Language Design
1

Currently java.lang.Boolean is converted to scala.Boolean implicitly.

  val javaBoolean:java.lang.Boolean = true
  if javaBoolean || true then {
    println("ok")
  }

According to sip-71 it will be forbidden to make implicit conversion without ‘into’ modifier in the future?

How will into modifier be used in such case?

Will it be allowed to create custom Boolean values transparently? It will be posible if into is used in if operator.

It can be useful for three-valued logic.

2

the compiler already does a bunch of special cases for interop with java, i would presume there would be a “classes considered into” setting baked into the compiler