Add LowerBounded and UpperBounded type classes

core/src/main/scala-2.12-/cats/instances/stream.scala

@@ -12,6 +12,9 @@ trait LazyListInstances extends StreamInstances with StreamInstancesBinCompat0 {
   val catsStdInstancesForLazyList = catsStdInstancesForStream
 }
 
+// For cross compile with backward compatibility
+trait LazyListInstancesBinCompat0
+
 trait StreamInstances extends cats.kernel.instances.StreamInstances {
 
   implicit val catsStdInstancesForStream
@@ -193,3 +196,5 @@ trait StreamInstancesBinCompat0 {
 
   }
 }
+
+trait StreamInstancesBinCompat1 extends cats.kernel.instances.StreamInstancesBinCompat0

core/src/main/scala-2.13+/cats/instances/lazyList.scala

@@ -7,6 +7,7 @@ import scala.annotation.tailrec
 
 //For cross compile with backward compatibility
 trait StreamInstancesBinCompat0
+trait StreamInstancesBinCompat1
 
 //For cross compile with backward compatibility
 trait StreamInstances extends LazyListInstances {
@@ -204,3 +205,5 @@ trait LazyListInstances extends cats.kernel.instances.StreamInstances {
 
   }
 }
+
+trait LazyListInstancesBinCompat0 extends cats.kernel.instances.StreamInstancesBinCompat0

core/src/main/scala/cats/implicits.scala

@@ -14,3 +14,4 @@ object implicits
     with instances.AllInstancesBinCompat3
     with instances.AllInstancesBinCompat4
     with instances.AllInstancesBinCompat5
+    with instances.AllInstancesBinCompat6

core/src/main/scala/cats/instances/all.scala

@@ -50,3 +50,14 @@ trait AllInstancesBinCompat3 extends AllCoreDurationInstances
 trait AllInstancesBinCompat4 extends SortedMapInstancesBinCompat1 with MapInstancesBinCompat1
 
 trait AllInstancesBinCompat5 extends SortedSetInstancesBinCompat0
+
+trait AllInstancesBinCompat6
+    extends EitherInstancesBinCompat0
+    with ListInstancesBinCompat1
+    with OptionInstancesBinCompat1
+    with QueueInstancesBinCompat0
+    with SetInstancesBinCompat0
+    with StreamInstancesBinCompat1
+    with TupleInstancesBinCompat0
+    with VectorInstancesBinCompat1
+    with UUIDInstancesBinCompat0

core/src/main/scala/cats/instances/either.scala

@@ -159,3 +159,5 @@ trait EitherInstances extends cats.kernel.instances.EitherInstances {
         }
     }
 }
+
+trait EitherInstancesBinCompat0 extends cats.kernel.instances.EitherInstancesBinCompat0

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

@@ -177,3 +177,5 @@ trait ListInstancesBinCompat0 {
         .value
   }
 }
+
+trait ListInstancesBinCompat1 extends cats.kernel.instances.ListInstancesBinCompat0

core/src/main/scala/cats/instances/option.scala

@@ -153,3 +153,5 @@ trait OptionInstancesBinCompat0 {
 
   }
 }
+
+trait OptionInstancesBinCompat1 extends cats.kernel.instances.OptionInstancesBinCompat0

core/src/main/scala/cats/instances/package.scala

@@ -9,6 +9,7 @@ package object instances {
       with AllInstancesBinCompat3
       with AllInstancesBinCompat4
       with AllInstancesBinCompat5
+      with AllInstancesBinCompat6
   object bigInt extends BigIntInstances
   object bigDecimal extends BigDecimalInstances
   object bitSet extends BitSetInstances
@@ -17,7 +18,7 @@ package object instances {
   object char extends CharInstances
   object double extends DoubleInstances
   object duration extends CoreDurationInstances with DurationInstances
-  object either extends EitherInstances
+  object either extends EitherInstances with EitherInstancesBinCompat0
   object eq extends EqInstances
   object equiv extends EquivInstances
   object float extends FloatInstances
@@ -26,26 +27,26 @@ package object instances {
   object future extends FutureInstances
   object int extends IntInstances
   object invariant extends InvariantMonoidalInstances
-  object list extends ListInstances with ListInstancesBinCompat0
+  object list extends ListInstances with ListInstancesBinCompat0 with ListInstancesBinCompat1
   object long extends LongInstances
-  object option extends OptionInstances with OptionInstancesBinCompat0
+  object option extends OptionInstances with OptionInstancesBinCompat0 with OptionInstancesBinCompat1
   object map extends MapInstances with MapInstancesBinCompat0 with MapInstancesBinCompat1
   object order extends OrderInstances
   object ordering extends OrderingInstances
   object parallel extends ParallelInstances
   object partialOrder extends PartialOrderInstances
   object partialOrdering extends PartialOrderingInstances
-  object queue extends QueueInstances
-  object set extends SetInstances
+  object queue extends QueueInstances with QueueInstancesBinCompat0
+  object set extends SetInstances with SetInstancesBinCompat0
   object short extends ShortInstances
   object sortedMap extends SortedMapInstances with SortedMapInstancesBinCompat0 with SortedMapInstancesBinCompat1
   object sortedSet extends SortedSetInstances with SortedSetInstancesBinCompat0
-  object stream extends StreamInstances with StreamInstancesBinCompat0
-  object lazyList extends LazyListInstances
+  object stream extends StreamInstances with StreamInstancesBinCompat0 with StreamInstancesBinCompat1
+  object lazyList extends LazyListInstances with LazyListInstancesBinCompat0
   object string extends StringInstances
   object try_ extends TryInstances
-  object tuple extends TupleInstances with Tuple2InstancesBinCompat0
+  object tuple extends TupleInstances with Tuple2InstancesBinCompat0 with TupleInstancesBinCompat0
   object unit extends UnitInstances
-  object uuid extends UUIDInstances
-  object vector extends VectorInstances with VectorInstancesBinCompat0
+  object uuid extends UUIDInstances with UUIDInstancesBinCompat0
+  object vector extends VectorInstances with VectorInstancesBinCompat0 with VectorInstancesBinCompat1
 }

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

@@ -153,3 +153,5 @@ trait QueueInstances extends cats.kernel.instances.QueueInstances {
         fa.iterator.map(_.show).mkString("Queue(", ", ", ")")
     }
 }
+
+trait QueueInstancesBinCompat0 extends cats.kernel.instances.QueueInstancesBinCompat0

core/src/main/scala/cats/instances/set.scala

@@ -44,3 +44,5 @@ trait SetInstances extends cats.kernel.instances.SetInstances {
       fa.toIterator.map(_.show).mkString("Set(", ", ", ")")
   }
 }
+
+trait SetInstancesBinCompat0 extends cats.kernel.instances.SetInstancesBinCompat0

core/src/main/scala/cats/instances/tuple.scala

@@ -7,6 +7,8 @@ import scala.annotation.tailrec
 
 trait TupleInstances extends Tuple2Instances with cats.kernel.instances.TupleInstances
 
+trait TupleInstancesBinCompat0 extends cats.kernel.instances.TupleInstancesBinCompat0
+
 trait Tuple2InstancesBinCompat0 {
 
   /**

core/src/main/scala/cats/instances/uuid.scala

@@ -7,3 +7,5 @@ trait UUIDInstances extends cats.kernel.instances.UUIDInstances {
   implicit val catsStdShowForUUID: Show[UUID] =
     Show.fromToString[UUID]
 }
+
+trait UUIDInstancesBinCompat0 extends cats.kernel.instances.UUIDInstancesBinCompat0

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

@@ -148,3 +148,5 @@ trait VectorInstancesBinCompat0 {
         .value
   }
 }
+
+trait VectorInstancesBinCompat1 extends cats.kernel.instances.VectorInstancesBinCompat0

kernel-laws/shared/src/main/scala/cats/kernel/laws/BoundedLaws.scala

@@ -0,0 +1,33 @@
+package cats.kernel.laws
+
+import cats.kernel.{LowerBounded, PartialOrder, UpperBounded}
+
+trait LowerBoundedLaws[A] extends PartialOrderLaws[A] {
+  implicit def B: LowerBounded[A]
+
+  def boundLteqv(x: A): IsEq[Boolean] =
+    E.lteqv(B.minBound, x) <-> true
+}
+
+object LowerBoundedLaws {
+  def apply[A](implicit ev: LowerBounded[A]): LowerBoundedLaws[A] =
+    new LowerBoundedLaws[A] {
+      def B: LowerBounded[A] = ev
+      def E: PartialOrder[A] = ev.partialOrder
+    }
+}
+
+trait UpperBoundedLaws[A] extends PartialOrderLaws[A] {
+  implicit def B: UpperBounded[A]
+
+  def boundGteqv(x: A): IsEq[Boolean] =
+    E.gteqv(B.maxBound, x) <-> true
+}
+
+object UpperBoundedLaws {
+  def apply[A](implicit ev: UpperBounded[A]): UpperBoundedLaws[A] =
+    new UpperBoundedLaws[A] {
+      def B: UpperBounded[A] = ev
+      def E: PartialOrder[A] = ev.partialOrder
+    }
+}

kernel-laws/shared/src/main/scala/cats/kernel/laws/discipline/BoundedTests.scala

@@ -0,0 +1,40 @@
+package cats
+package kernel
+package laws
+package discipline
+
+import cats.kernel.instances.boolean._
+import org.scalacheck.Arbitrary
+import org.scalacheck.Prop.forAll
+
+trait LowerBoundedTests[A] extends PartialOrderTests[A] {
+  def laws: LowerBoundedLaws[A]
+
+  def lowerBounded(implicit arbA: Arbitrary[A], arbF: Arbitrary[A => A], eqOA: Eq[Option[A]], eqA: Eq[A]): RuleSet =
+    new DefaultRuleSet(
+      "lowerBounded",
+      Some(partialOrder),
+      "bound is less than or equals" -> forAll(laws.boundLteqv _)
+    )
+}
+
+object LowerBoundedTests {
+  def apply[A: LowerBounded]: LowerBoundedTests[A] =
+    new LowerBoundedTests[A] { def laws: LowerBoundedLaws[A] = LowerBoundedLaws[A] }
+}
+
+trait UpperBoundedTests[A] extends PartialOrderTests[A] {
+  def laws: UpperBoundedLaws[A]
+
+  def upperBounded(implicit arbA: Arbitrary[A], arbF: Arbitrary[A => A], eqOA: Eq[Option[A]], eqA: Eq[A]): RuleSet =
+    new DefaultRuleSet(
+      "upperBounded",
+      Some(partialOrder),
+      "bound is greater than or equals" -> forAll(laws.boundGteqv _)
+    )
+}
+
+object UpperBoundedTests {
+  def apply[A: UpperBounded]: UpperBoundedTests[A] =
+    new UpperBoundedTests[A] { def laws: UpperBoundedLaws[A] = UpperBoundedLaws[A] }
+}

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

@@ -176,6 +176,39 @@ class Tests extends AnyFunSuiteLike with Discipline {
   checkAll("Order.reverse(Order.reverse(Order[Int]))", OrderTests(Order.reverse(Order.reverse(Order[Int]))).order)
   checkAll("Order.fromLessThan[Int](_ < _)", OrderTests(Order.fromLessThan[Int](_ < _)).order)
 
+  checkAll("LowerBounded[Unit]", LowerBoundedTests[Unit].lowerBounded)
+  checkAll("LowerBounded[Boolean]", LowerBoundedTests[Boolean].lowerBounded)
+  checkAll("LowerBounded[Byte]", LowerBoundedTests[Byte].lowerBounded)
+  checkAll("LowerBounded[Short]", LowerBoundedTests[Short].lowerBounded)
+  checkAll("LowerBounded[Char]", LowerBoundedTests[Char].lowerBounded)
+  checkAll("LowerBounded[Int]", LowerBoundedTests[Int].lowerBounded)
+  checkAll("LowerBounded[Long]", LowerBoundedTests[Long].lowerBounded)
+  checkAll("LowerBounded[Duration]", LowerBoundedTests[Duration].lowerBounded)
+  checkAll("LowerBounded[FiniteDuration]", LowerBoundedTests[FiniteDuration].lowerBounded)
+  checkAll("LowerBounded[UUID]", LowerBoundedTests[UUID].lowerBounded)
+  checkAll("LowerBounded[String]", LowerBoundedTests[String].lowerBounded)
+  checkAll("LowerBounded[Symbol]", LowerBoundedTests[Symbol].lowerBounded)
+  checkAll("LowerBounded[Option[Int]]", LowerBoundedTests[Option[Int]].lowerBounded)
+  checkAll("LowerBounded[Either[Int, String]]", LowerBoundedTests[Either[Int, String]].lowerBounded)
+  checkAll("LowerBounded[List[Int]]", LowerBoundedTests[List[Int]].lowerBounded)
+  checkAll("LowerBounded[Queue[Int]]", LowerBoundedTests[Queue[Int]].lowerBounded)
+  checkAll("LowerBounded[Set[Int]]", LowerBoundedTests[Set[Int]].lowerBounded)
+  checkAll("LowerBounded[Stream[Int]]", LowerBoundedTests[LazyList[Int]].lowerBounded)
+  checkAll("LowerBounded[Vector[Int]]", LowerBoundedTests[Vector[Int]].lowerBounded)
+
+  checkAll("UpperBounded[Unit]", UpperBoundedTests[Unit].upperBounded)
+  checkAll("UpperBounded[Boolean]", UpperBoundedTests[Boolean].upperBounded)
+  checkAll("UpperBounded[Byte]", UpperBoundedTests[Byte].upperBounded)
+  checkAll("UpperBounded[Short]", UpperBoundedTests[Short].upperBounded)
+  checkAll("UpperBounded[Char]", UpperBoundedTests[Char].upperBounded)
+  checkAll("UpperBounded[Int]", UpperBoundedTests[Int].upperBounded)
+  checkAll("UpperBounded[Long]", UpperBoundedTests[Long].upperBounded)
+  checkAll("UpperBounded[Duration]", UpperBoundedTests[Duration].upperBounded)
+  checkAll("UpperBounded[FiniteDuration]", UpperBoundedTests[FiniteDuration].upperBounded)
+  checkAll("UpperBounded[UUID]", UpperBoundedTests[UUID].upperBounded)
+  checkAll("UpperBounded[Option[Int]]", UpperBoundedTests[Option[Int]].upperBounded)
+  checkAll("UpperBounded[Either[String, Int]]", UpperBoundedTests[Either[String, Int]].upperBounded)
+
   checkAll("Monoid[String]", MonoidTests[String].monoid)
   checkAll("Monoid[String]", SerializableTests.serializable(Monoid[String]))
   checkAll("Monoid[Option[Int]]", MonoidTests[Option[Int]].monoid)

kernel/src/main/scala/cats/kernel/Bounded.scala

@@ -0,0 +1,43 @@
+package cats.kernel
+
+import scala.{specialized => sp}
+
+/**
+ * A type class used to name the lower limit of a type.
+ */
+trait LowerBounded[@sp A] {
+  def partialOrder: PartialOrder[A]
+
+  /**
+   * Returns the lower limit of a type.
+   */
+  def minBound: A
+}
+
+trait LowerBoundedFunctions[L[T] <: LowerBounded[T]] {
+  def minBound[@sp A](implicit ev: L[A]): A = ev.minBound
+}
+
+object LowerBounded extends LowerBoundedFunctions[LowerBounded] {
+  @inline def apply[A](implicit l: LowerBounded[A]): LowerBounded[A] = l
+}
+
+/**
+ * A type class used to name the upper limit of a type.
+ */
+trait UpperBounded[@sp A] {
+  def partialOrder: PartialOrder[A]
+
+  /**
+   * Returns the upper limit of a type.
+   */
+  def maxBound: A
+}
+
+trait UpperBoundedFunctions[U[T] <: UpperBounded[T]] {
+  def maxBound[@sp A](implicit ev: U[A]): A = ev.maxBound
+}
+
+object UpperBounded extends UpperBoundedFunctions[UpperBounded] {
+  @inline def apply[A](implicit u: UpperBounded[A]): UpperBounded[A] = u
+}

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

@@ -34,3 +34,14 @@ trait AllInstances
     with VectorInstances
 
 trait AllInstancesBinCompat0 extends FiniteDurationInstances
+
+trait AllInstancesBinCompat1
+    extends EitherInstancesBinCompat0
+    with ListInstancesBinCompat0
+    with OptionInstancesBinCompat0
+    with QueueInstancesBinCompat0
+    with SetInstancesBinCompat0
+    with StreamInstancesBinCompat0
+    with TupleInstancesBinCompat0
+    with UUIDInstancesBinCompat0
+    with VectorInstancesBinCompat0

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

@@ -2,11 +2,16 @@ package cats.kernel
 package instances
 
 trait BooleanInstances {
-  implicit val catsKernelStdOrderForBoolean: Order[Boolean] with Hash[Boolean] =
-    new BooleanOrder
+  implicit val catsKernelStdOrderForBoolean
+    : Order[Boolean] with Hash[Boolean] with LowerBounded[Boolean] with UpperBounded[Boolean] = new BooleanOrder
 }
 
-class BooleanOrder extends Order[Boolean] with Hash[Boolean] {
+trait BooleanBounded extends LowerBounded[Boolean] with UpperBounded[Boolean] {
+  override def minBound: Boolean = false
+  override def maxBound: Boolean = true
+}
+
+class BooleanOrder extends Order[Boolean] with Hash[Boolean] with BooleanBounded { self =>
 
   def hash(x: Boolean): Int = x.hashCode()
   def compare(x: Boolean, y: Boolean): Int =
@@ -21,4 +26,6 @@ class BooleanOrder extends Order[Boolean] with Hash[Boolean] {
 
   override def min(x: Boolean, y: Boolean): Boolean = x && y
   override def max(x: Boolean, y: Boolean): Boolean = x || y
+
+  override val partialOrder: PartialOrder[Boolean] = self
 }

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

@@ -2,18 +2,24 @@ package cats.kernel
 package instances
 
 trait ByteInstances {
-  implicit val catsKernelStdOrderForByte: Order[Byte] with Hash[Byte] = new ByteOrder
+  implicit val catsKernelStdOrderForByte: Order[Byte] with Hash[Byte] with LowerBounded[Byte] with UpperBounded[Byte] =
+    new ByteOrder
   implicit val catsKernelStdGroupForByte: CommutativeGroup[Byte] = new ByteGroup
 }
 
+trait ByteBounded extends LowerBounded[Byte] with UpperBounded[Byte] {
+  override def minBound: Byte = Byte.MinValue
+  override def maxBound: Byte = Byte.MaxValue
+}
+
 class ByteGroup extends CommutativeGroup[Byte] {
   def combine(x: Byte, y: Byte): Byte = (x + y).toByte
   def empty: Byte = 0
   def inverse(x: Byte): Byte = (-x).toByte
   override def remove(x: Byte, y: Byte): Byte = (x - y).toByte
 }
 
-class ByteOrder extends Order[Byte] with Hash[Byte] {
+class ByteOrder extends Order[Byte] with Hash[Byte] with ByteBounded { self =>
 
   def hash(x: Byte): Int = x.hashCode()
 
@@ -31,4 +37,6 @@ class ByteOrder extends Order[Byte] with Hash[Byte] {
     java.lang.Math.min(x.toInt, y.toInt).toByte
   override def max(x: Byte, y: Byte): Byte =
     java.lang.Math.max(x.toInt, y.toInt).toByte
+
+  override val partialOrder: PartialOrder[Byte] = self
 }