Merge pull request #768 from satorg/fix-core-warnings

Fix warnings in `core` module

Author: gemelen

core/src/main/scala/cats/collections/BitSet.scala

@@ -559,7 +559,7 @@ object BitSet {
         BitSet.adoptedUnion(this, rhs)
       } else {
         // height == rhs.height, so we know rhs is a Branch.
-        val Branch(_, _, rcs) = rhs
+        val Branch(_, _, rcs) = rhs: @unchecked
         val cs = new Array[BitSet](32)
         var i = 0
         while (i < 32) {
@@ -591,7 +591,7 @@ object BitSet {
         Empty
       } else {
         // height == rhs.height, so we know rhs is a Branch.
-        val Branch(_, _, rcs) = rhs
+        val Branch(_, _, rcs) = rhs: @unchecked
         val cs = new Array[BitSet](32)
         var i = 0
         var nonEmpty = false
@@ -629,7 +629,7 @@ object BitSet {
         false
       } else {
         // height == rhs.height, so we know rhs is a Branch.
-        val Branch(_, _, rcs) = rhs
+        val Branch(_, _, rcs) = rhs: @unchecked
         var i = 0
         while (i < 32) {
           val x = children(i)
@@ -674,7 +674,7 @@ object BitSet {
         this | rhs
       } else {
         // height == rhs.height, so we know rhs is a Branch.
-        val Branch(_, _, rcs) = rhs
+        val Branch(_, _, rcs) = rhs: @unchecked
         val cs = new Array[BitSet](32)
         var i = 0
         while (i < 32) {
@@ -791,7 +791,7 @@ object BitSet {
         throw InternalError("branch misaligned")
       } else {
         // height == rhs.height, so we know rhs is a Branch.
-        val Branch(_, _, rcs) = rhs
+        val Branch(_, _, rcs) = rhs: @unchecked
         var i = 0
         while (i < 32) {
           val x = children(i)

core/src/main/scala/cats/collections/Dequeue.scala

@@ -233,8 +233,8 @@ sealed abstract class Dequeue[+A] {
               SingletonDequeue(a)
             else
               FullDequeue(NonEmptyList(a, List.empty), 1, bl.toList.asInstanceOf[NonEmptyList[B]], bs - 1)
-          case (Some(f), Some(b)) =>
-            fl += f
+          case (Some(ff), Some(b)) =>
+            fl += ff
             bl += b
             FullDequeue(fl.toList.asInstanceOf[NonEmptyList[B]],
                         fs,

core/src/main/scala/cats/collections/DisjointSets.scala

@@ -113,7 +113,8 @@ class DisjointSets[T: Order] private (private val entries: AvlMap[T, Entry[T]])
    */
   def toSets: (DisjointSets[T], AvlMap[T, AvlSet[T]]) =
     entries.foldLeft((this, AvlMap[T, AvlSet[T]]())) { case ((dsets, acc), (k, _)) =>
-      val (newSt, Some(label)) = dsets.find(k)
+      // Each `k` is from the `entries`` map, so it must be found.
+      val (newSt, Some(label)) = dsets.find(k): @unchecked
       val updatedSet = acc.get(label).getOrElse(AvlSet.empty[T]) + k
       (newSt, acc + (label -> updatedSet))
     }

core/src/main/scala/cats/collections/Heap.scala

@@ -392,7 +392,7 @@ object Heap {
       val sb = new java.lang.StringBuilder
       sb.append("Heap(")
       f.foldLeft(false) { (notFirst, a) =>
-        if (notFirst) sb.append(", ")
+        if (notFirst) sb.append(", "): Unit
         sb.append(s.show(a))
         true
       }

core/src/main/scala/cats/collections/Map.scala

@@ -173,8 +173,8 @@ trait AvlMapInstances {
 
     override def tailRecM[A, B](a: A)(f: A => AvlMap[K, Either[A, B]]): AvlMap[K, B] = {
       @tailrec def extract(kv: (K, Either[A, B])): AvlSet[(K, B)] = kv._2 match {
-        case Left(a) =>
-          f(a).get(kv._1) match {
+        case Left(aa) =>
+          f(aa).get(kv._1) match {
             case Some(x) => extract(kv._1 -> x)
             case _       => AvlSet.empty[(K, B)]
           }

core/src/main/scala/cats/collections/PairingHeap.scala

@@ -336,7 +336,7 @@ object PairingHeap {
       val sb = new java.lang.StringBuilder
       sb.append("PairingHeap(")
       f.foldLeft(false) { (notFirst, a) =>
-        if (notFirst) sb.append(", ")
+        if (notFirst) sb.append(", "): Unit
         sb.append(s.show(a))
         true
       }

core/src/main/scala/cats/collections/Set.scala

@@ -376,7 +376,8 @@ object AvlSet extends AvlSetInstances {
         left match {
           case Branch(lv, ll, lr) =>
             if (rotation(ll.height, lr.height, 0) < 0) {
-              val Branch(lrv, lrl, lrr) = lr
+              // If `lr` is taller than `ll`, then `lr` cannot be empty.
+              val Branch(lrv, lrl, lrr) = lr: @unchecked
               Branch(lrv, Branch(lv, ll, lrl), Branch(value, lrr, right))
             } else {
               Branch(lv, ll, Branch(value, lr, right))
@@ -387,7 +388,8 @@ object AvlSet extends AvlSetInstances {
         right match {
           case Branch(rv, rl, rr) =>
             if (rotation(rl.height, rr.height, 0) > 0) {
-              val Branch(rlv, rll, rlr) = rl
+              // If `rl` is taller than `rr`, then `rl` cannot be empty.
+              val Branch(rlv, rll, rlr) = rl: @unchecked
               Branch(rlv, Branch(value, left, rll), Branch(rv, rlr, rr))
             } else {
               Branch(rv, Branch(value, left, rl), rr)

core/src/main/scala/cats/collections/TreeList.scala

@@ -199,7 +199,7 @@ sealed abstract class TreeList[+A] {
       l.uncons match {
         case None => ()
         case Some((h, t)) =>
-          if (!first) strb.append(", ")
+          if (!first) strb.append(", "): Unit
           strb.append(h.toString)
           loop(false, t)
       }
@@ -807,7 +807,7 @@ object TreeList extends TreeListInstances0 {
           fa match {
             case NonEmpty(_, tail) =>
               loop(tail, fn(fa) :: revList)
-            case Empty => fromListReverse(revList)
+            case _ => fromListReverse(revList)
           }
         loop(fa, Nil)
       }
@@ -919,10 +919,10 @@ object TreeList extends TreeListInstances0 {
                   either match {
                     case Right(b) =>
                       loop(rest :: tail, b :: acc)
-                    case Left(a) =>
-                      loop(fn(a) :: rest :: tail, acc)
+                    case Left(aa) =>
+                      loop(fn(aa) :: rest :: tail, acc)
                   }
-                case Empty =>
+                case _ =>
                   loop(tail, acc)
               }
             case Nil => acc