implicitNotFound for BuildFrom

[lrytz]

scala> class Lst[+A] {
     |   def map[B, That](f: A => B)(implicit bf: strawman.collection.BuildFrom[Lst[A], B, That]): That = scala.Predef.???
     | }
defined class Lst

scala> object Test {
     |   def foo(l: Lst[scala.Int]) = l.map[scala.Int, Lst[scala.Predef.String]](x => 1)
     | }
         def foo(l: Lst[scala.Int]) = l.map[scala.Int, Lst[scala.Predef.String]](x => 1)
                                                                                ^
On line 2: error: Cannot construct a collection of type Lst[String] with elements of type Int based on a collection of type Lst[Int].

This is an existing test case in scala/scala: https://github.com/scala/scala/blob/2.13.x/test/files/neg/t2462a.check