Scala 3 not applying Scala 2 implicit conversions in the precense of subtyping about dotty

[EugeneFlesselle]

This is definitely an issue, given the following minimization:

import scala.language.implicitConversions

trait Trace
trait ToTrace[A]

given ToTrace[String] = ???

object Test:
  type H = "Hello"
  val s: H = ???

  locally:
    given [A: ToTrace]: Conversion[A, Trace] = ???
    val _: Trace = s : String // ok
    val _: Trace = s // ok
  
  locally:
    implicit def conversion[A: ToTrace](a: A): Trace = ???
    val _: Trace = s : String // ok
    val _: Trace = s : "Hello" // ok
    val _: Trace = s // error