2.13.0-RC1

.travis.yml

@@ -14,7 +14,7 @@ jdk:
 
 scala_version_211: &scala_version_211 2.11.12
 scala_version_212: &scala_version_212 2.12.7
-scala_version_213: &scala_version_213 2.13.0-M5
+scala_version_213: &scala_version_213 2.13.0-RC1
 
 before_install:
  - export PATH=${PATH}:./vendor/bundle

build.sbt

@@ -83,13 +83,13 @@ lazy val catsSettings = Seq(
     "bintray/non".at("http://dl.bintray.com/non/maven")
   ),
   libraryDependencies ++= Seq(
-    "org.typelevel" %%% "machinist" % "0.6.6",
-    compilerPlugin("org.spire-math" %% "kind-projector" % "0.9.9")
+    "org.typelevel" %%% "machinist" % "0.6.7",
+    compilerPlugin("org.typelevel" %% "kind-projector" % "0.10.0")
   ) ++ macroDependencies(scalaVersion.value),
 ) ++ commonSettings ++ publishSettings ++ scoverageSettings ++ simulacrumSettings
 
 lazy val simulacrumSettings = Seq(
-  libraryDependencies += "com.github.mpilquist" %%% "simulacrum" % "0.15.0" % Provided,
+  libraryDependencies += "com.github.mpilquist" %%% "simulacrum" % "0.16.0" % Provided,
   pomPostProcess := { (node: xml.Node) =>
     new RuleTransformer(new RewriteRule {
       override def transform(node: xml.Node): Seq[xml.Node] = node match {
@@ -151,20 +151,19 @@ lazy val includeGeneratedSrc: Setting[_] = {
   }
 }
 
-def scalatestVersion(scalaVersion: String): String =
-  if (priorTo2_13(scalaVersion)) "3.0.5" else "3.0.6-SNAP5"
+val scalatestVersion = "3.0.8-RC2"
 
 val scalaCheckVersion = "1.14.0"
 
-val disciplineVersion = "0.10.0"
+val disciplineVersion = "0.11.1"
 
 lazy val disciplineDependencies = Seq(
   libraryDependencies += "org.scalacheck" %%% "scalacheck" % scalaCheckVersion,
   libraryDependencies += "org.typelevel" %%% "discipline" % disciplineVersion
 )
 
 lazy val testingDependencies = Seq(
-  libraryDependencies += "org.scalatest" %%% "scalatest" % scalatestVersion(scalaVersion.value) % "test"
+  libraryDependencies += "org.scalatest" %%% "scalatest" % scalatestVersion % "test"
 )
 
 lazy val docsMappingsAPIDir = settingKey[String]("Name of subdirectory in site target directory for api docs")
@@ -549,6 +548,7 @@ lazy val tests = crossProject(JSPlatform, JVMPlatform)
   .settings(noPublishSettings)
   .jsSettings(commonJsSettings)
   .jvmSettings(commonJvmSettings)
+  .settings(scalacOptions in Test := (scalacOptions in Test).value.filter(_ != "-Xfatal-warnings"))
 
 lazy val testkit = crossProject(JSPlatform, JVMPlatform)
   .crossType(CrossType.Pure)
@@ -558,9 +558,10 @@ lazy val testkit = crossProject(JSPlatform, JVMPlatform)
   .settings(moduleName := "cats-testkit")
   .settings(catsSettings)
   .settings(disciplineDependencies)
-  .settings(libraryDependencies += "org.scalatest" %%% "scalatest" % scalatestVersion(scalaVersion.value))
+  .settings(libraryDependencies += "org.scalatest" %%% "scalatest" % scalatestVersion)
   .jsSettings(commonJsSettings)
   .jvmSettings(commonJvmSettings)
+  .settings(scalacOptions := scalacOptions.value.filter(_ != "-Xfatal-warnings"))
 
 lazy val alleycatsCore = crossProject(JSPlatform, JVMPlatform)
   .crossType(CrossType.Pure)
@@ -596,6 +597,7 @@ lazy val alleycatsTests = crossProject(JSPlatform, JVMPlatform)
   .settings(noPublishSettings)
   .jsSettings(commonJsSettings)
   .jvmSettings(commonJvmSettings)
+  .settings(scalacOptions in Test := (scalacOptions in Test).value.filter(_ != "-Xfatal-warnings"))
 
 // bench is currently JVM-only
 
@@ -628,7 +630,7 @@ lazy val binCompatTest = project
         else //We are not testing BC on Scala 2.13 yet.
           "org.typelevel" %% "cats-core" % version.value % Provided
       },
-      "org.scalatest" %%% "scalatest" % scalatestVersion(scalaVersion.value) % Test
+      "org.scalatest" %%% "scalatest" % scalatestVersion % Test
     )
   )
   .dependsOn(core.jvm % Test)

core/src/main/scala/cats/ApplicativeError.scala

@@ -82,7 +82,7 @@ trait ApplicativeError[F[_], E] extends Applicative[F] {
    * `F[A]` values.
    */
   def recover[A](fa: F[A])(pf: PartialFunction[E, A]): F[A] =
-    handleErrorWith(fa)(e => (pf.andThen(pure)).applyOrElse(e, raiseError))
+    handleErrorWith(fa)(e => (pf.andThen(pure _)).applyOrElse(e, raiseError _))
 
   /**
    * Recover from certain errors by mapping them to an `F[A]` value.

core/src/main/scala/cats/MonadError.scala

@@ -44,7 +44,7 @@ trait MonadError[F[_], E] extends ApplicativeError[F, E] with Monad[F] {
    * ApplicativeError in Cats 2.0: see [[https://github.com/typelevel/cats/issues/2685]]
    */
   def adaptError[A](fa: F[A])(pf: PartialFunction[E, E]): F[A] =
-    recoverWith(fa)(pf.andThen(raiseError))
+    recoverWith(fa)(pf.andThen(raiseError[A] _))
 
   /**
    * Inverse of `attempt`

core/src/main/scala/cats/data/WriterT.scala

@@ -357,6 +357,9 @@ sealed private[data] trait WriterTFlatMap1[F[_], L] extends WriterTApply[F, L] w
   implicit override def F0: FlatMap[F]
   implicit def L0: Monoid[L]
 
+  override def ap[A, B](f: WriterT[F, L, A => B])(fa: WriterT[F, L, A]): WriterT[F, L, B] =
+    super[WriterTApply].ap(f)(fa)
+
   def flatMap[A, B](fa: WriterT[F, L, A])(f: A => WriterT[F, L, B]): WriterT[F, L, B] =
     fa.flatMap(f)
 

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

@@ -134,10 +134,10 @@ class SortedMapHash[K, V](implicit V: Hash[V], O: Order[K], K: Hash[K])
     var c = 1
     x.foreach {
       case (k, v) =>
-        val h = StaticMethods.product2Hash(K.hash(k), V.hash(v))
+        val h = StaticMethods.product2HashWithPrefix(K.hash(k), V.hash(v), "Tuple2")
         a += h
         b ^= h
-        if (h != 0) c *= h
+        c = StaticMethods.updateUnorderedHashC(c, h)
         n += 1
     }
     var h = mapSeed

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

@@ -103,7 +103,7 @@ class SortedSetHash[A: Order: Hash] extends Hash[SortedSet[A]] {
       val h = Hash[A].hash(x)
       a += h
       b ^= h
-      if (h != 0) c *= h
+      c = cats.kernel.instances.StaticMethods.updateUnorderedHashC(c, h)
       n += 1
     }
     var h = setSeed

core/src/main/scala/cats/syntax/applicativeError.scala

@@ -123,5 +123,5 @@ final class ApplicativeErrorOps[F[_], E, A](private val fa: F[A]) extends AnyVal
    * to `ApplicativeError` in Cats 2.0: see [[https://github.com/typelevel/cats/issues/2685]]
    */
   def adaptErr(pf: PartialFunction[E, E])(implicit F: ApplicativeError[F, E]): F[A] =
-    F.recoverWith(fa)(pf.andThen(F.raiseError))
+    F.recoverWith(fa)(pf.andThen(F.raiseError[A] _))
 }

core/src/main/scala/cats/syntax/monadError.scala

@@ -24,7 +24,7 @@ final class MonadErrorOps[F[_], E, A](private val fa: F[A]) extends AnyVal {
    */
   def reject(pf: PartialFunction[A, E])(implicit F: MonadError[F, E]): F[A] =
     F.flatMap(fa) { a =>
-      pf.andThen(F.raiseError[A]).applyOrElse(a, (_: A) => fa)
+      pf.andThen(F.raiseError[A] _).applyOrElse(a, (_: A) => fa)
     }
 
   def adaptError(pf: PartialFunction[E, E])(implicit F: MonadError[F, E]): F[A] =

kernel/src/main/scala-2.12-/cats/kernel/compat/HashCompat.scala

@@ -0,0 +1,53 @@
+package cats
+package kernel
+package compat
+
+private[kernel] class HashCompat {
+  // Adapted from scala.util.hashing.MurmurHash#productHash.
+  private[kernel] def product1HashWithPrefix(_1Hash: Int, prefix: String): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var h = productSeed
+    h = mix(h, _1Hash)
+    finalizeHash(h, 1)
+  }
+
+  // Adapted from scala.util.hashing.MurmurHash#productHash.
+  private[cats] def product2HashWithPrefix(_1Hash: Int, _2Hash: Int, prefix: String): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var h = productSeed
+    h = mix(h, _1Hash)
+    h = mix(h, _2Hash)
+    finalizeHash(h, 2)
+  }
+
+  private[cats] def updateUnorderedHashC(c: Int, h: Int): Int = if (h != 0) c * h else c
+
+  // 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-2.13+/cats/kernel/compat/HashCompat.scala

@@ -0,0 +1,116 @@
+package cats
+package kernel
+package compat
+
+private[kernel] class HashCompat {
+  // Adapted from scala.util.hashing.MurmurHash#productHash.
+  private[kernel] def product1HashWithPrefix(_1Hash: Int, prefix: String): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var h = productSeed
+    h = mix(h, prefix.hashCode)
+    h = mix(h, _1Hash)
+    finalizeHash(h, 1)
+  }
+
+  // Adapted from scala.util.hashing.MurmurHash#productHash.
+  private[cats] def product2HashWithPrefix(_1Hash: Int, _2Hash: Int, prefix: String): Int = {
+    import scala.util.hashing.MurmurHash3._
+    var h = productSeed
+    h = mix(h, prefix.hashCode)
+    h = mix(h, _1Hash)
+    h = mix(h, _2Hash)
+    finalizeHash(h, 2)
+  }
+
+  private[cats] def updateUnorderedHashC(c: Int, h: Int): Int = c * (h | 1)
+
+  // 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.{finalizeHash, mix, rangeHash, seqSeed}
+    var n = 0
+    var h = seqSeed
+    var rangeState = 0 // 0 = no data, 1 = first elem read, 2 = has valid diff, 3 = invalid
+    var rangeDiff = 0
+    var prev = 0
+    var initial = 0
+    var elems = x
+    while (!elems.isEmpty) {
+      val head = elems.head
+      val tail = elems.tail
+      val hash = A.hash(head)
+      h = mix(h, hash)
+      rangeState match {
+        case 0 =>
+          initial = hash
+          rangeState = 1
+        case 1 =>
+          rangeDiff = hash - prev
+          rangeState = 2
+        case 2 =>
+          if (rangeDiff != hash - prev) rangeState = 3
+        case _ =>
+      }
+      prev = hash
+      n += 1
+      elems = tail
+    }
+    if (rangeState == 2) rangeHash(initial, rangeDiff, prev, seqSeed)
+    else 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.{finalizeHash, mix, seqSeed}
+
+    val it = xs.iterator
+    var h = seqSeed
+    // scalastyle:off
+    if (!it.hasNext) return finalizeHash(h, 0)
+    // scalastyle:on
+    val x0 = it.next()
+    // scalastyle:off
+    if (!it.hasNext) return finalizeHash(mix(h, A.hash(x0)), 1)
+    // scalastyle:on
+    val x1 = it.next()
+
+    val initial = A.hash(x0)
+    h = mix(h, initial)
+    val h0 = h
+    var prev = A.hash(x1)
+    val rangeDiff = prev - initial
+    var i = 2
+    while (it.hasNext) {
+      h = mix(h, prev)
+      val hash = A.hash(it.next())
+      if (rangeDiff != hash - prev) {
+        h = mix(h, hash)
+        i += 1
+        while (it.hasNext) {
+          h = mix(h, A.hash(it.next()))
+          i += 1
+        }
+        // scalastyle:off
+        return finalizeHash(h, i)
+        // scalastyle:on
+      }
+      prev = hash
+      i += 1
+    }
+    avalanche(mix(mix(h0, rangeDiff), prev))
+  }
+
+  // adapted from scala.util.hashing.MurmurHash3
+  /** Force all bits of the hash to avalanche. Used for finalizing the hash. */
+  final protected def avalanche(hash: Int): Int = {
+    var h = hash
+
+    h ^= h >>> 16
+    h *= 0x85ebca6b
+    h ^= h >>> 13
+    h *= 0xc2b2ae35
+    h ^= h >>> 16
+
+    h
+  }
+}

kernel/src/main/scala-2.13+/cats/kernel/compat/WrappedMutableMapBase.scala

@@ -5,5 +5,5 @@ import scala.collection.mutable
 
 abstract private[kernel] class WrappedMutableMapBase[K, V](m: mutable.Map[K, V]) extends Map[K, V] with Serializable {
   def updated[V2 >: V](key: K, value: V2): Map[K, V2] = m.toMap + ((key, value))
-  def remove(key: K): Map[K, V] = m.toMap - key
+  def removed(key: K): Map[K, V] = m.toMap - key
 }

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

@@ -4,7 +4,7 @@ package instances
 
 import scala.collection.mutable
 
-object StaticMethods {
+object StaticMethods extends cats.kernel.compat.HashCompat {
 
   def wrapMutableMap[K, V](m: mutable.Map[K, V]): Map[K, V] =
     new WrappedMutableMap(m)
@@ -96,34 +96,4 @@ 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/either/package.scala

@@ -100,7 +100,7 @@ class EitherEq[A, B](implicit A: Eq[A], B: Eq[B]) extends Eq[Either[A, B]] {
 class EitherHash[A, B](implicit A: Hash[A], B: Hash[B]) extends EitherEq[A, B] with Hash[Either[A, B]] {
   def hash(x: Either[A, B]): Int =
     x match {
-      case Left(xx)  => StaticMethods.product1Hash(A.hash(xx))
-      case Right(xx) => StaticMethods.product1Hash(B.hash(xx))
+      case Left(xx)  => StaticMethods.product1HashWithPrefix(A.hash(xx), "Left")
+      case Right(xx) => StaticMethods.product1HashWithPrefix(B.hash(xx), "Right")
     }
 }

kernel/src/main/scala/cats/kernel/instances/map/package.scala

@@ -30,10 +30,10 @@ class MapHash[K, V](implicit V: Hash[V]) extends MapEq[K, V]()(V) with Hash[Map[
     x.foreach {
       case (k, v) =>
         // use the default hash on keys because that's what Scala's Map does
-        val h = StaticMethods.product2Hash(k.hashCode(), V.hash(v))
+        val h = StaticMethods.product2HashWithPrefix(k.hashCode(), V.hash(v), "Tuple2")
         a += h
         b ^= h
-        if (h != 0) c *= h
+        c = StaticMethods.updateUnorderedHashC(c, h)
         n += 1
     }
     var h = mapSeed