implicit conversion does not favor by-value conversions first, unlike Scala 2

class A
class B

object Test {
  implicit def a2b(a: A): B = ???
  implicit def byName_a2b(a: => A): B = ???

  def test(a: A): Unit = {
    val b: B = a
  }
}

With scalac, compilation succeeds, and the typechecked tree for test is:

val b: B = Test.this.a2b(a)

But with dotty, it fails with:

-- [E007] Type Mismatch Error: try/ambimp2.scala -------------------------------
9 |    val b: B = a
  |               ^
  |found:    A(a)
  |required: B
  |
  |
  |Note that implicit conversions cannot be applied because they are ambiguous;
  | both method byName_a2b in object Test and method a2b in object Test convert from A(a) to B

[smarter]

@felixmulder I’ve replaced your example with a minimized version and changed the title to reflect the real problem.

[smarter]

What about using the old rule under -language:Scala2 ?