More tests that work now

Author: odersky

tests/pos/i15160.scala

@@ -0,0 +1,17 @@
+trait Eq[A] {
+  def eqv(a1: A, a2: A): Boolean
+}
+
+given stringEq: Eq[String] with {
+  def eqv(a1: String, a2: String) = a1 == a2
+}
+
+abstract class Newtype[Src] {
+  opaque type Type = Src
+
+  protected final def derive[F[_]](using ev: F[Src]): F[Type] = ev
+}
+
+object Sample extends Newtype[String] {
+  given eq: Eq[Type] = derive
+}

tests/pos/i15670.scala

@@ -0,0 +1,29 @@
+trait JsonRowEntry {
+  def readAs[E](implicit c: Read[E]): Option[E] = ???
+}
+trait Read[T]
+trait Codec[T] extends Read[T]
+trait CodecTypeProjection[C[_]]
+object JsonTransform  {
+  given SetCodec[T, C[_]: CodecTypeProjection]: scala.Conversion[C[T], C[Set[T]]] = ???
+  given SetCodecExp[T, C[_]: CodecTypeProjection](using codec: C[T]): C[Set[T]] = codec
+  given Codec[String] = ???
+  given CodecTypeProjection[Read] = ???
+}
+
+@main def Test() = {
+  import JsonTransform.given
+  val tree = new JsonRowEntry {}
+  tree.readAs[Set[String]]
+}
+
+trait Box[E]
+
+trait Domain
+
+def fun[E, D[_] <: Domain](box: Box[E])(implicit domain: D[E]): Unit = {
+
+  val newBox: Box[E] =  ???
+
+  fun(newBox)
+}

tests/pos/i15820.scala

@@ -0,0 +1,8 @@
+sealed trait Domain[E]
+
+final def splitBounds[E, D[X] <: Domain[X]](
+    bounds: Seq[E],
+  )( using domain: D[E]): Seq[E] =
+      val newBounds: Seq[E] = ???
+      splitBounds(newBounds) // does not compile
+      splitBounds[E,D](newBounds) // does compile