Drop StrictIterableFactory in favor of caps.Pure constraints

Author: natsukagami

library/src/scala/collection/Factory.scala

@@ -293,57 +293,17 @@ object IterableFactory {
   }
 }
 
-/** IterableFactory but with strict operations that do not capture the inputs. */
-trait StrictIterableFactory[+CC[_] <: caps.Pure] extends IterableFactory[CC] {
-  // pure overrides of the IterableFactory methods
-  override def from[A](source: IterableOnce[A]^): CC[A]
-
-  override def iterate[A](start: A, len: Int)(f: A => A): CC[A] = from(new View.Iterate(start, len)(f))
-
-  override def unfold[A, S](init: S)(f: S => Option[(A, S)]): CC[A] = from(new View.Unfold(init)(f))
-
-  override def fill[A](n: Int)(elem: => A): CC[A] = from(new View.Fill(n)(elem))
-
-  override def fill[A](n1: Int, n2: Int)(elem: => A): CC[CC[A] @uncheckedVariance] = fill(n1)(fill(n2)(elem))
-
-  override def fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): CC[CC[CC[A]] @uncheckedVariance] = fill(n1)(fill(n2, n3)(elem))
-
-  override def fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): CC[CC[CC[CC[A]]] @uncheckedVariance] =
-    fill(n1)(fill(n2, n3, n4)(elem))
-
-  override def fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): CC[CC[CC[CC[CC[A]]]] @uncheckedVariance] =
-    fill(n1)(fill(n2, n3, n4, n5)(elem))
-
-  override def tabulate[A](n: Int)(f: Int => A): CC[A] = from(new View.Tabulate(n)(f))
-
-  override def tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): CC[CC[A] @uncheckedVariance] =
-    tabulate(n1)(i1 => tabulate(n2)(f(i1, _)))
-
-  override def tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): CC[CC[CC[A]] @uncheckedVariance] =
-    tabulate(n1)(i1 => tabulate(n2, n3)(f(i1, _, _)))
-
-  override def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): CC[CC[CC[CC[A]]] @uncheckedVariance] =
-    tabulate(n1)(i1 => tabulate(n2, n3, n4)(f(i1, _, _, _)))
-
-  override def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) => A): CC[CC[CC[CC[CC[A]]]] @uncheckedVariance] =
-    tabulate(n1)(i1 => tabulate(n2, n3, n4, n5)(f(i1, _, _, _, _)))
-
-  override def concat[A](xss: Iterable[A]*): CC[A] = {
-    from(xss.foldLeft(View.empty[A])(_ ++ _))
-  }
-}
-
 /**
   * @tparam CC Collection type constructor (e.g. `List`)
   */
-trait SeqFactory[+CC[A] <: StrictSeqOps[A, Seq, Seq[A]]] extends StrictIterableFactory[CC] {
+trait SeqFactory[+CC[A] <: SeqOps[A, Seq, Seq[A]] & caps.Pure] extends IterableFactory[CC] {
   import SeqFactory.UnapplySeqWrapper
   final def unapplySeq[A](x: CC[A] @uncheckedVariance): UnapplySeqWrapper[A] = new UnapplySeqWrapper(x) // TODO is uncheckedVariance sound here?
 }
 
 object SeqFactory {
   @SerialVersionUID(3L)
-  class Delegate[CC[A] <: StrictSeqOps[A, Seq, Seq[A]]](delegate: SeqFactory[CC]) extends SeqFactory[CC] {
+  class Delegate[CC[A] <: SeqOps[A, Seq, Seq[A]] & caps.Pure](delegate: SeqFactory[CC]) extends SeqFactory[CC] {
     override def apply[A](elems: A*): CC[A] = delegate.apply(elems: _*)
     def empty[A]: CC[A] = delegate.empty
     def from[E](it: IterableOnce[E]^): CC[E] = delegate.from(it)
@@ -363,7 +323,7 @@ object SeqFactory {
   }
 }
 
-trait StrictOptimizedSeqFactory[+CC[A] <: StrictSeqOps[A, Seq, Seq[A]]] extends SeqFactory[CC] {
+trait StrictOptimizedSeqFactory[+CC[A] <: SeqOps[A, Seq, Seq[A]] & caps.Pure] extends SeqFactory[CC] {
 
   override def fill[A](n: Int)(elem: => A): CC[A] = {
     val b = newBuilder[A]