more instances for Hash (#1712): Queue/Duration (#1950)

* more instances to Hash: Queue/Duration

* more instances to Hash: Queue/Duration

kernel-laws/src/test/scala/cats/kernel/laws/LawTests.scala

@@ -111,10 +111,12 @@ class LawTests extends FunSuite with Discipline {
   laws[HashLaws, BigDecimal].check(_.hash)
   laws[HashLaws, BigInt].check(_.hash)
   laws[HashLaws, UUID].check(_.hash)
+  laws[HashLaws, Duration].check(_.hash)
   laws[HashLaws, List[Int]].check(_.hash)
   laws[HashLaws, Option[String]].check(_.hash)
   laws[HashLaws, List[String]].check(_.hash)
   laws[HashLaws, Vector[Int]].check(_.hash)
+  laws[HashLaws, Queue[Int]].check(_.hash)
   laws[HashLaws, Stream[Int]].check(_.hash)
   laws[HashLaws, Set[Int]].check(_.hash)
   laws[HashLaws, (Int, String)].check(_.hash)
@@ -139,6 +141,7 @@ class LawTests extends FunSuite with Discipline {
   laws[HashLaws, List[Int]].check(_.sameAsUniversalHash)
   laws[HashLaws, Option[String]].check(_.sameAsUniversalHash)
   laws[HashLaws, List[String]].check(_.sameAsUniversalHash)
+  laws[HashLaws, Queue[Int]].check(_.sameAsUniversalHash)
   laws[HashLaws, Vector[Int]].check(_.sameAsUniversalHash)
   laws[HashLaws, Stream[Int]].check(_.sameAsUniversalHash)
   laws[HashLaws, Set[Int]].check(_.sameAsUniversalHash)
@@ -160,11 +163,13 @@ class LawTests extends FunSuite with Discipline {
   laws[HashLaws, BigDecimal].check(_.sameAsScalaHashing)
   laws[HashLaws, BigInt].check(_.sameAsScalaHashing)
   laws[HashLaws, UUID].check(_.sameAsScalaHashing)
+  laws[HashLaws, Duration].check(_.sameAsScalaHashing)
 
   laws[HashLaws, Option[HasHash[Int]]].check(_.hash)
   laws[HashLaws, List[HasHash[Int]]].check(_.hash)
   laws[HashLaws, Vector[HasHash[Int]]].check(_.hash)
   laws[HashLaws, Stream[HasHash[Int]]].check(_.hash)
+  laws[HashLaws, Queue[HasHash[Int]]].check(_.hash)
 
   laws[OrderLaws, List[HasEq[Int]]].check(_.eqv)
   laws[OrderLaws, Option[HasEq[Int]]].check(_.eqv)

kernel/src/main/scala/cats/kernel/instances/StaticMethods.scala

@@ -96,4 +96,34 @@ object StaticMethods {
     h = mix(h, _2Hash)
     finalizeHash(h, 2)
   }
+
+  // adapted from [[scala.util.hashing.MurmurHash3]],
+  // but modified standard `Any#hashCode` to `ev.hash`.
+  def listHash[A](x: List[A])(implicit A: Hash[A]): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var n = 0
+    var h = seqSeed
+    var elems = x
+    while (!elems.isEmpty) {
+      val head = elems.head
+      val tail = elems.tail
+      h = mix(h, A.hash(head))
+      n += 1
+      elems = tail
+    }
+    finalizeHash(h, n)
+  }
+
+  // adapted from scala.util.hashing.MurmurHash3
+  def orderedHash[A](xs: TraversableOnce[A])(implicit A: Hash[A]): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var n = 0
+    var h = seqSeed
+    xs foreach { x =>
+      h = mix(h, A.hash(x))
+      n += 1
+    }
+    finalizeHash(h, n)
+  }
+
 }

kernel/src/main/scala/cats/kernel/instances/duration.scala

@@ -6,7 +6,7 @@ import scala.concurrent.duration.Duration
 package object duration extends DurationInstances
 
 trait DurationInstances {
-  implicit val catsKernelStdOrderForDuration: Order[Duration] = new DurationOrder
+  implicit val catsKernelStdOrderForDuration: Order[Duration] with Hash[Duration] = new DurationOrder
   implicit val catsKernelStdGroupForDuration: CommutativeGroup[Duration] = new DurationGroup
 }
 
@@ -18,7 +18,9 @@ trait DurationInstances {
  * The value Duration.Undefined breaks our laws, because undefined
  * values are not equal to themselves.
  */
-class DurationOrder extends Order[Duration] {
+class DurationOrder extends Order[Duration] with Hash[Duration] {
+  def hash(x: Duration): Int = x.hashCode()
+
   def compare(x: Duration, y: Duration): Int = x compare y
 
   override def eqv(x: Duration, y: Duration): Boolean = x == y

kernel/src/main/scala/cats/kernel/instances/list.scala

@@ -62,22 +62,7 @@ class ListPartialOrder[A](implicit ev: PartialOrder[A]) extends PartialOrder[Lis
 }
 
 class ListHash[A](implicit ev: Hash[A]) extends ListEq[A]()(ev) with Hash[List[A]] {
-  // adapted from [[scala.util.hashing.MurmurHash3]],
-  // but modified standard `Any#hashCode` to `ev.hash`.
-  import scala.util.hashing.MurmurHash3._
-  def hash(x: List[A]): Int = {
-    var n = 0
-    var h = seqSeed
-    var elems = x
-    while (!elems.isEmpty) {
-      val head = elems.head
-      val tail = elems.tail
-      h = mix(h, ev.hash(head))
-      n += 1
-      elems = tail
-    }
-    finalizeHash(h, n)
-  }
+  def hash(x: List[A]): Int = StaticMethods.listHash(x)(ev)
 }
 
 class ListEq[A](implicit ev: Eq[A]) extends Eq[List[A]] {

kernel/src/main/scala/cats/kernel/instances/queue.scala

@@ -15,6 +15,9 @@ trait QueueInstances extends QueueInstances1 {
 trait QueueInstances1 extends QueueInstances2 {
   implicit def catsKernelStdPartialOrderForQueue[A: PartialOrder]: PartialOrder[Queue[A]] =
     new QueuePartialOrder[A]
+
+  implicit def catsKernelStdHashForQueue[A: Hash]: Hash[Queue[A]] =
+    new QueueHash[A]
 }
 
 trait QueueInstances2 {
@@ -28,6 +31,10 @@ class QueueOrder[A](implicit ev: Order[A]) extends Order[Queue[A]] {
     else StaticMethods.iteratorCompare(xs.iterator, ys.iterator)
 }
 
+class QueueHash[A](implicit ev: Hash[A]) extends QueueEq[A] with Hash[Queue[A]] {
+  def hash(x: Queue[A]): Int = StaticMethods.orderedHash(x)
+}
+
 class QueuePartialOrder[A](implicit ev: PartialOrder[A]) extends PartialOrder[Queue[A]] {
   def partialCompare(xs: Queue[A], ys: Queue[A]): Double =
     if (xs eq ys) 0.0

kernel/src/main/scala/cats/kernel/instances/stream.scala

@@ -36,17 +36,7 @@ class StreamPartialOrder[A](implicit ev: PartialOrder[A]) extends PartialOrder[S
 }
 
 class StreamHash[A](implicit ev: Hash[A]) extends StreamEq[A]()(ev) with Hash[Stream[A]] {
-  import scala.util.hashing.MurmurHash3._
-  // adapted from scala.util.hashing.MurmurHash3
-  def hash(xs: Stream[A]): Int = {
-    var n = 0
-    var h = seqSeed
-    xs foreach { x =>
-      h = mix(h, ev.hash(x))
-      n += 1
-    }
-    finalizeHash(h, n)
-  }
+  def hash(xs: Stream[A]): Int = StaticMethods.orderedHash(xs)
 }
 
 class StreamEq[A](implicit ev: Eq[A]) extends Eq[Stream[A]] {

kernel/src/main/scala/cats/kernel/instances/vector.scala

@@ -35,18 +35,8 @@ class VectorPartialOrder[A](implicit ev: PartialOrder[A]) extends PartialOrder[V
     else StaticMethods.iteratorPartialCompare(xs.iterator, ys.iterator)
 }
 
-class VectorHash[A](implicit ev: Hash[A]) extends VectorEq[A]()(ev) with Hash[Vector[A]] {
-  // adapted from scala.util.hashing
-  import scala.util.hashing.MurmurHash3._
-  def hash(xs: Vector[A]): Int = {
-    var n = 0
-    var h = seqSeed
-    xs foreach { x =>
-      h = mix(h, ev.hash(x))
-      n += 1
-    }
-    finalizeHash(h, n)
-  }
+class VectorHash[A](implicit ev: Hash[A]) extends VectorEq[A] with Hash[Vector[A]] {
+  def hash(xs: Vector[A]): Int = StaticMethods.orderedHash(xs)
 }
 
 class VectorEq[A](implicit ev: Eq[A]) extends Eq[Vector[A]] {