Update scala2-library-cc to make use of inference fixes

Most hacks using `asInstanceOf` or `???` are no longer necessary.

Author: odersky

scala2-library-cc/src/scala/collection/Factory.scala

@@ -161,7 +161,7 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @return  A $coll that contains the results of `n1 x n2` evaluations of `elem`.
     */
   def fill[A](n1: Int, n2: Int)(elem: => A): CC[(CC[A]^{elem}) @uncheckedVariance]^{elem} =
-  	fill[CC[A]^{elem}](n1)(fill(n2)(elem)) // !!! explicit type argument required under cc
+  	fill(n1)(fill(n2)(elem))
 
   /** Produces a three-dimensional $coll containing the results of some element computation a number of times.
     *  @param   n1  the number of elements in the 1st dimension
@@ -170,8 +170,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @param   elem the element computation
     *  @return  A $coll that contains the results of `n1 x n2 x n3` evaluations of `elem`.
     */
-  def fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): CC[(CC[CC[A]^{elem}]^{elem}) @uncheckedVariance]^{elem} = // !!! problem with checking rhs under cc
-    fill[CC[CC[A]^{elem}]^{elem}](n1)(fill(n2, n3)(elem)) // !!! explicit type argument required under cc
+  def fill[A](n1: Int, n2: Int, n3: Int)(elem: => A): CC[(CC[CC[A]^{elem}]^{elem}) @uncheckedVariance]^{elem} =
+    fill(n1)(fill(n2, n3)(elem))
 
   /** Produces a four-dimensional $coll containing the results of some element computation a number of times.
     *  @param   n1  the number of elements in the 1st dimension
@@ -181,8 +181,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @param   elem the element computation
     *  @return  A $coll that contains the results of `n1 x n2 x n3 x n4` evaluations of `elem`.
     */
-  def fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): CC[(CC[CC[CC[A]^{elem}]^{elem}]^{elem}) @uncheckedVariance]^{elem} = // !!! problem with checking rhs under cc
-    fill[CC[CC[CC[A]^{elem}]^{elem}]^{elem}](n1)(fill(n2, n3, n4)(elem)) // !!! explicit type argument required under cc
+  def fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: => A): CC[(CC[CC[CC[A]^{elem}]^{elem}]^{elem}) @uncheckedVariance]^{elem} =
+    fill(n1)(fill(n2, n3, n4)(elem))
 
   /** Produces a five-dimensional $coll containing the results of some element computation a number of times.
     *  @param   n1  the number of elements in the 1st dimension
@@ -193,9 +193,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @param   elem the element computation
     *  @return  A $coll that contains the results of `n1 x n2 x n3 x n4 x n5` evaluations of `elem`.
     */
-  def fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): CC[(CC[CC[CC[CC[A]^{elem}]^{elem}]^{elem}]^{elem}) @uncheckedVariance]^{elem} = // !!! problem with checking rhs under cc
-    fill[CC[CC[CC[CC[A]^{elem}]^{elem}]^{elem}]^{elem}](n1)(fill(n2, n3, n4, n5)(elem)) // !!! explicit type argument required under cc
-
+  def fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: => A): CC[(CC[CC[CC[CC[A]^{elem}]^{elem}]^{elem}]^{elem}) @uncheckedVariance]^{elem} =
+    fill(n1)(fill(n2, n3, n4, n5)(elem))
 
   /** Produces a $coll containing values of a given function over a range of integer values starting from 0.
     *  @param  n   The number of elements in the $coll
@@ -211,8 +210,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @return A $coll consisting of elements `f(i1, i2)`
     *          for `0 <= i1 < n1` and `0 <= i2 < n2`.
     */
-  def tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): CC[CC[A] @uncheckedVariance]^{f} = // !!! problem with checking rhs under cc
-    ??? // tabulate(n1)(i1 => tabulate(n2)(f(i1, _)))
+  def tabulate[A](n1: Int, n2: Int)(f: (Int, Int) => A): CC[(CC[A]^{f}) @uncheckedVariance]^{f} =
+    tabulate(n1)(i1 => tabulate(n2)(f(i1, _)))
 
   /** Produces a three-dimensional $coll containing values of a given function over ranges of integer values starting from 0.
     *  @param   n1  the number of elements in the 1st dimension
@@ -222,8 +221,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @return A $coll consisting of elements `f(i1, i2, i3)`
     *          for `0 <= i1 < n1`, `0 <= i2 < n2`, and `0 <= i3 < n3`.
     */
-  def tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): CC[CC[CC[A]] @uncheckedVariance]^{f} = // !!! problem with checking rhs under cc
-    ??? // tabulate(n1)(i1 => tabulate(n2, n3)(f(i1, _, _)))
+  def tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) => A): CC[(CC[CC[A]^{f}]^{f}) @uncheckedVariance]^{f} =
+    tabulate(n1)(i1 => tabulate(n2, n3)(f(i1, _, _)))
 
   /** Produces a four-dimensional $coll containing values of a given function over ranges of integer values starting from 0.
     *  @param   n1  the number of elements in the 1st dimension
@@ -234,8 +233,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @return A $coll consisting of elements `f(i1, i2, i3, i4)`
     *          for `0 <= i1 < n1`, `0 <= i2 < n2`, `0 <= i3 < n3`, and `0 <= i4 < n4`.
     */
-  def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): CC[CC[CC[CC[A]]] @uncheckedVariance]^{f} = // !!! problem with checking rhs under cc
-    ??? // tabulate(n1)(i1 => tabulate(n2, n3, n4)(f(i1, _, _, _)))
+  def tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) => A): CC[(CC[CC[CC[A]^{f}]^{f}]^{f}) @uncheckedVariance]^{f} =
+    tabulate(n1)(i1 => tabulate(n2, n3, n4)(f(i1, _, _, _)))
 
   /** Produces a five-dimensional $coll containing values of a given function over ranges of integer values starting from 0.
     *  @param   n1  the number of elements in the 1st dimension
@@ -247,8 +246,8 @@ trait IterableFactory[+CC[_]] extends Serializable, Pure {
     *  @return A $coll consisting of elements `f(i1, i2, i3, i4, i5)`
     *          for `0 <= i1 < n1`, `0 <= i2 < n2`, `0 <= i3 < n3`, `0 <= i4 < n4`, and `0 <= i5 < n5`.
     */
-  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]^{f} = // !!! problem with checking rhs under cc
-    ??? // tabulate(n1)(i1 => tabulate(n2, n3, n4, n5)(f(i1, _, _, _, _)))
+  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]^{f}]^{f}]^{f}]^{f}) @uncheckedVariance]^{f} =
+    tabulate(n1)(i1 => tabulate(n2, n3, n4, n5)(f(i1, _, _, _, _)))
 
   /** Concatenates all argument collections into a single $coll.
    *

scala2-library-cc/src/scala/collection/Iterable.scala

@@ -397,7 +397,7 @@ trait IterableOps[+A, +CC[_], +C] extends Any with IterableOnce[A] with Iterable
       if (i != headSize)
         fail
     }
-    iterableFactory.from(bs.map(_.result())).asInstanceOf // !!! needed for cc
+    iterableFactory.from(bs.map(_.result()))
   }
 
   def filter(pred: A => Boolean): C^{this, pred} = fromSpecific(new View.Filter(this, pred, isFlipped = false))

scala2-library-cc/src/scala/collection/MapView.scala

@@ -81,7 +81,7 @@ object MapView extends MapViewFactory {
 
   @SerialVersionUID(3L)
   object EmptyMapView extends AbstractMapView[Any, Nothing] {
-  // !!! cc problem: crash when we replace the line with
+  // !!! cc problem? type mismatch when we replace the line with
   // private val EmptyMapView: MapView[Any, Nothing] = new AbstractMapView[Any, Nothing] {
     override def get(key: Any): Option[Nothing] = None
     override def iterator: Iterator[Nothing] = Iterator.empty[Nothing]

scala2-library-cc/src/scala/collection/concurrent/TrieMap.scala

@@ -1183,10 +1183,7 @@ private[collection] class TrieMapIterator[K, V](var level: Int, private var ct:
         stack(d) = arr1
         stackpos(d) = -1
         val it = newIterator(level + 1, ct, _mustInit = false)
-        val xss: Array[Array[BasicNode]] = it.stack.asInstanceOf
-          // !!! cc split into separate xss and asInstanceOf needed because cc gets confused with
-          // two-dimensinal invariant arrays
-        xss(0) = arr2
+        it.stack(0) = arr2
         it.stackpos(0) = -1
         it.depth = 0
         it.advance() // <-- fix it

scala2-library-cc/src/scala/collection/immutable/HashMap.scala

@@ -2384,7 +2384,7 @@ private[immutable] final class HashMapBuilder[K, V] extends ReusableBuilder[(K,
             )
             currentValueCursor += 1
           }
-        }.asInstanceOf // !!! cc gets confused with representation of capture sets in invariant position
+        }
       case hm: collection.mutable.HashMap[K, V] =>
         val iter = hm.nodeIterator
         while (iter.hasNext) {

scala2-library-cc/src/scala/collection/immutable/HashSet.scala

@@ -2101,7 +2101,7 @@ private[collection] final class HashSetBuilder[A] extends ReusableBuilder[A, Has
             )
             currentValueCursor += 1
           }
-        }.asInstanceOf // !!! cc gets confused with representation of capture sets in invariant position
+        }
       case other =>
         val it = other.iterator
         while(it.hasNext) addOne(it.next())