Merge branch 'master' into update/sbt-pgp-2.0.1-M3

.travis.yml

@@ -10,7 +10,7 @@ git:
 jdk:
   - openjdk8
 
-scala_version_211: &scala_version_211 2.11.12
+
 scala_version_212: &scala_version_212 2.12.9
 scala_version_213: &scala_version_213 2.13.0
 
@@ -34,22 +34,17 @@ jobs:
       install: pip install --user codecov
       script: sbt coverage buildJVM bench/test coverageReport && codecov
 
-    - &js_tests
-      stage: test
+    - stage: test
       env: TEST="JS tests"
       # http://austinpray.com/ops/2015/09/20/change-travis-node-version.html
       install: rm -rf ~/.nvm && git clone https://github.com/creationix/nvm.git ~/.nvm && (cd ~/.nvm && git checkout `git describe --abbrev=0 --tags`) && source ~/.nvm/nvm.sh && nvm install $TRAVIS_NODE_VERSION
       script: sbt ++$TRAVIS_SCALA_VERSION! validateJS && sbt ++$TRAVIS_SCALA_VERSION! validateKernelJS && sbt ++$TRAVIS_SCALA_VERSION! validateFreeJS
-      scala: *scala_version_211
-    - <<: *js_tests
       scala: *scala_version_212
 
     - &jvm_tests
       stage: test
       env: TEST="JVM tests"
       script: sbt ++$TRAVIS_SCALA_VERSION! buildJVM bench/test
-      scala: *scala_version_211
-    - <<: *jvm_tests
       scala: *scala_version_212
     - <<: *jvm_tests
       scala: *scala_version_213
@@ -65,12 +60,9 @@ jobs:
       env: TEST="scalafix"
       script: cd scalafix && sbt tests/test
 
-    - &bincompat_check
-      stage: test
+    - stage: test
       env: TEST="binary compatibility"
       script: sbt ++$TRAVIS_SCALA_VERSION! validateBC
-      scala: *scala_version_211
-    - <<: *bincompat_check
       scala: *scala_version_212
 
     - stage: styling

README.md

@@ -182,6 +182,7 @@ By sharing the same set of type classes, instances and data types provided by Ca
  * [scala-forex](https://github.com/snowplow/scala-forex): exchange rate lookups
  * [scala-maxmind-ip-lookups](https://github.com/snowplow/scala-maxmind-iplookups): IP geolocation through [the Maxmind database](https://www.maxmind.com/en/home)
  * [scala-referer-parser](https://github.com/snowplow-referer-parser/scala-referer-parser): referer parsing
+ * [scala-rl](https://github.com/sritchie/scala-rl): Functional, monadic reinforcement learning in Scala
  * [scala-weather](https://github.com/snowplow/scala-weather): weather lookups
  * [scanamo](https://github.com/guardian/scanamo): simpler DynamoDB access for Scala
  * [seals](https://github.com/durban/seals): tools for schema evolution and language-integrated schemata
@@ -280,6 +281,7 @@ Here's a (non-exhaustive) list of companies that use Cats in production. Don't s
 - [Codecentric](https://codecentric.de)
 - [Colisweb](https://www.colisweb.com/)
 - [Coya](https://coya.com/)
+- [Datum Brain](https://datumbrain.com/)
 - [DriveTribe](https://drivetribe.com/)
 - [Dwolla](https://dwolla.com/)
 - [Earnest](https://www.earnest.com)

binCompatTest/src/main/scala/catsBC/MimaExceptions.scala

@@ -1,4 +1,5 @@
 package catsBC
+import cats.InjectK
 import cats.implicits._
 
 object MimaExceptions {
@@ -27,6 +28,7 @@ object MimaExceptions {
     true.iterateUntilM(Option(_))(identity _),
     Either.catchOnly[NumberFormatException] { "foo".toInt },
     (1.validNel[String], 2.validNel[String], 3.validNel[String]) mapN (_ + _ + _),
-    (1.asRight[String], 2.asRight[String], 3.asRight[String]) parMapN (_ + _ + _)
+    (1.asRight[String], 2.asRight[String], 3.asRight[String]) parMapN (_ + _ + _),
+    InjectK.catsReflexiveInjectKInstance[Option]
   )
 }

build.sbt

@@ -50,8 +50,6 @@ def scalaVersionSpecificFolders(srcName: String, srcBaseDir: java.io.File, scala
     List(CrossType.Pure, CrossType.Full)
       .flatMap(_.sharedSrcDir(srcBaseDir, srcName).toList.map(f => file(f.getPath + suffix)))
   CrossVersion.partialVersion(scalaVersion) match {
-    case Some((2, y)) if y <= 12 =>
-      extraDirs("-2.12-")
     case Some((2, y)) if y >= 13 =>
       extraDirs("-2.13+")
     case _ => Nil
@@ -65,6 +63,8 @@ lazy val commonScalaVersionSettings = Seq(
 
 commonScalaVersionSettings
 
+ThisBuild / mimaFailOnNoPrevious := false
+
 lazy val commonSettings = commonScalaVersionSettings ++ Seq(
   scalacOptions ++= commonScalacOptions(scalaVersion.value),
   Compile / unmanagedSourceDirectories ++= scalaVersionSpecificFolders("main", baseDirectory.value, scalaVersion.value),
@@ -82,7 +82,7 @@ lazy val commonSettings = commonScalaVersionSettings ++ Seq(
     val docSource = (sources in (Compile, doc)).value
     if (priorTo2_13(scalaVersion.value)) docSource else Nil
   }
-) ++ warnUnusedImport ++ update2_12 ++ xlint
+) ++ warnUnusedImport
 
 def macroDependencies(scalaVersion: String) =
   CrossVersion.partialVersion(scalaVersion) match {
@@ -152,11 +152,6 @@ lazy val commonJvmSettings = Seq(
   Test / javaOptions := Seq("-Xmx3G")
 )
 
-lazy val commonNativeSettings = Seq(
-  scalaVersion := "2.11.12", // TODO: load scala version form .travis.yml: https://github.com/dwijnand/sbt-travisci/issues/11
-  crossScalaVersions := Seq("2.11.12")
-)
-
 lazy val includeGeneratedSrc: Setting[_] = {
   mappings in (Compile, packageSrc) ++= {
     val base = (sourceManaged in Compile).value
@@ -397,7 +392,18 @@ def mimaSettings(moduleName: String) =
           exclude[IncompatibleMethTypeProblem]("cats.arrow.FunctionKMacros.lift"),
           exclude[MissingTypesProblem]("cats.arrow.FunctionKMacros$"),
           exclude[IncompatibleMethTypeProblem]("cats.arrow.FunctionKMacros#Lifter.this"),
-          exclude[IncompatibleResultTypeProblem]("cats.arrow.FunctionKMacros#Lifter.c")
+          exclude[IncompatibleResultTypeProblem]("cats.arrow.FunctionKMacros#Lifter.c"),
+          exclude[DirectMissingMethodProblem]("cats.arrow.FunctionKMacros.compatNewTypeName")
+        ) ++ //package private classes no longer needed
+        Seq(
+          exclude[MissingClassProblem]("cats.kernel.compat.scalaVersionMoreSpecific$"),
+          exclude[MissingClassProblem]("cats.kernel.compat.scalaVersionMoreSpecific"),
+          exclude[MissingClassProblem](
+            "cats.kernel.compat.scalaVersionMoreSpecific$suppressUnusedImportWarningForScalaVersionMoreSpecific"
+          )
+        ) ++ // Only narrowing of types allowed here
+        Seq(
+          exclude[IncompatibleSignatureProblem]("*")
         )
     }
   )
@@ -651,9 +657,12 @@ lazy val bench = project
   .enablePlugins(JmhPlugin)
 
 lazy val binCompatTest = project
-  .disablePlugins(CoursierPlugin)
   .settings(noPublishSettings)
   .settings(
+    // workaround because coursier doesn't understand dependsOn(core.jvm % Test)
+    // see https://github.com/typelevel/cats/pull/3079#discussion_r327181584
+    // see https://github.com/typelevel/cats/pull/3026#discussion_r321984342
+    useCoursier := false,
     commonScalaVersionSettings,
     addCompilerPlugin("org.typelevel" %% "kind-projector" % kindProjectorVersion),
     libraryDependencies ++= List(
@@ -788,7 +797,7 @@ addCommandAlias("validateKernelJS", "kernelLawsJS/test")
 addCommandAlias("validateFreeJS", "freeJS/test") //separated due to memory constraint on travis
 addCommandAlias("validate", ";clean;validateJS;validateKernelJS;validateFreeJS;validateJVM")
 
-addCommandAlias("prePR", ";fmt;++2.11.12 mimaReportBinaryIssues")
+addCommandAlias("prePR", "fmt")
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Base Build Settings - Should not need to edit below this line.
@@ -827,7 +836,8 @@ def commonScalacOptions(scalaVersion: String) =
     "-Ywarn-numeric-widen",
     "-Ywarn-value-discard",
     "-Xfatal-warnings",
-    "-deprecation"
+    "-deprecation",
+    "-Xlint:-unused,_"
   ) ++ (if (priorTo2_13(scalaVersion))
           Seq(
             "-Yno-adapted-args",
@@ -878,15 +888,7 @@ lazy val sharedReleaseProcess = Seq(
 )
 
 lazy val warnUnusedImport = Seq(
-  scalacOptions ++= {
-    CrossVersion.partialVersion(scalaVersion.value) match {
-      case Some((2, 11)) =>
-        Seq("-Ywarn-unused-import")
-      case Some((2, n)) if n >= 12 =>
-        Seq("-Ywarn-unused:imports")
-
-    }
-  },
+  scalacOptions ++= Seq("-Ywarn-unused:imports"),
   scalacOptions in (Compile, console) ~= { _.filterNot(Set("-Ywarn-unused-import", "-Ywarn-unused:imports")) },
   scalacOptions in (Test, console) := (scalacOptions in (Compile, console)).value
 )
@@ -898,21 +900,3 @@ lazy val credentialSettings = Seq(
     password <- Option(System.getenv().get("SONATYPE_PASSWORD"))
   } yield Credentials("Sonatype Nexus Repository Manager", "oss.sonatype.org", username, password)).toSeq
 )
-
-lazy val update2_12 = Seq(
-  scalacOptions -= {
-    CrossVersion.partialVersion(scalaVersion.value) match {
-      case Some((2, scalaMajor)) if scalaMajor >= 12 => "-Yinline-warnings"
-      case _                                         => ""
-    }
-  }
-)
-
-lazy val xlint = Seq(
-  scalacOptions += {
-    CrossVersion.partialVersion(scalaVersion.value) match {
-      case Some((2, scalaMajor)) if scalaMajor >= 12 => "-Xlint:-unused,_"
-      case _                                         => "-Xlint"
-    }
-  }
-)

core/src/main/scala-2.12-/cats/instances/ScalaVersionSpecificParallelInstances.scala → core/src/main/scala-2.12/cats/instances/ScalaVersionSpecificParallelInstances.scala

@@ -22,7 +22,7 @@ trait ParallelInstances extends ParallelInstances1 {
     }
 
   @deprecated("Use OptionT.catsDataParallelForOptionT", "2.0.0")
-  private[instances] def catsParallelForOptionTNestedOption[M[_]](
+  def catsParallelForOptionTNestedOption[M[_]](
     implicit P: Parallel[M]
   ): Parallel.Aux[OptionT[M, *], Nested[P.F, Option, *]] = OptionT.catsDataParallelForOptionT[M]
 
@@ -69,7 +69,7 @@ trait ParallelInstances extends ParallelInstances1 {
     }
 
   @deprecated("Use EitherT.catsDataParallelForEitherTWithParallelEffect", "2.0.0")
-  private[instances] def catsParallelForEitherTNestedParallelValidated[M[_], E: Semigroup](
+  def catsParallelForEitherTNestedParallelValidated[M[_], E: Semigroup](
     implicit P: Parallel[M]
   ): Parallel.Aux[EitherT[M, E, *], Nested[P.F, Validated[E, *], *]] =
     EitherT.catsDataParallelForEitherTWithParallelEffect[M, E]

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

@@ -22,7 +22,7 @@ trait ParallelInstances extends ParallelInstances1 {
     }
 
   @deprecated("Use OptionT.catsDataParallelForOptionT", "2.0.0")
-  private[instances] def catsParallelForOptionTNestedOption[M[_]](
+  def catsParallelForOptionTNestedOption[M[_]](
     implicit P: Parallel[M]
   ): Parallel.Aux[OptionT[M, *], Nested[P.F, Option, *]] = OptionT.catsDataParallelForOptionT[M]
 
@@ -84,7 +84,7 @@ trait ParallelInstances extends ParallelInstances1 {
     }
 
   @deprecated("Use EitherT.catsDataParallelForEitherTWithParallelEffect", "2.0.0")
-  private[instances] def catsParallelForEitherTNestedParallelValidated[M[_], E: Semigroup](
+  def catsParallelForEitherTNestedParallelValidated[M[_], E: Semigroup](
     implicit P: Parallel[M]
   ): Parallel.Aux[EitherT[M, E, *], Nested[P.F, Validated[E, *], *]] =
     EitherT.catsDataParallelForEitherTWithParallelEffect[M, E]

core/src/main/scala/cats/Inject.scala

@@ -1,7 +1,5 @@
 package cats
 
-import kernel.compat.scalaVersionMoreSpecific._
-
 /**
  * Inject is a type class providing an injection from type `A` into
  * type `B`. An injection is a function `inj` which does not destroy
@@ -27,7 +25,6 @@ abstract class Inject[A, B] {
   final def unapply(b: B): Option[A] = prj(b)
 }
 
-@suppressUnusedImportWarningForScalaVersionMoreSpecific
 sealed abstract private[cats] class InjectInstances {
   implicit def catsReflexiveInjectInstance[A]: Inject[A, A] =
     new Inject[A, A] {

core/src/main/scala/cats/InjectK.scala

@@ -2,7 +2,6 @@ package cats
 
 import cats.arrow.FunctionK
 import cats.data.EitherK
-import kernel.compat.scalaVersionMoreSpecific._
 
 /**
  * InjectK is a type class providing an injection from type
@@ -33,7 +32,6 @@ abstract class InjectK[F[_], G[_]] {
   final def unapply[A](ga: G[A]): Option[F[A]] = prj(ga)
 }
 
-@suppressUnusedImportWarningForScalaVersionMoreSpecific
 sealed abstract private[cats] class InjectKInstances {
   implicit def catsReflexiveInjectKInstance[F[_]]: InjectK[F, F] =
     new InjectK[F, F] {

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

@@ -24,7 +24,7 @@ sealed abstract private[data] class OpInstances extends OpInstances0 {
     new OpEq[Arr, A, B] { def Arr: Eq[Arr[B, A]] = ArrEq }
 
   @deprecated("Use catsDataEqForOp", "2.0.0-RC2")
-  private[data] def catsKernelEqForOp[Arr[_, _], A, B](implicit ArrEq: Eq[Arr[B, A]]): Eq[Op[Arr, A, B]] =
+  def catsKernelEqForOp[Arr[_, _], A, B](implicit ArrEq: Eq[Arr[B, A]]): Eq[Op[Arr, A, B]] =
     catsDataEqForOp[Arr, A, B]
 }
 

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

@@ -8,7 +8,7 @@ import cats.{~>, Applicative, Monad, Parallel}
 
 private[instances] trait ParallelInstances1 {
   @deprecated("Use EitherT.catsDataParallelForEitherTWithSequentialEffect", "2.0.0")
-  private[instances] def catsParallelForEitherTNestedValidated[M[_]: Monad, E: Semigroup]
+  def catsParallelForEitherTNestedValidated[M[_]: Monad, E: Semigroup]
     : Parallel.Aux[EitherT[M, E, *], Nested[M, Validated[E, *], *]] =
     new Parallel[EitherT[M, E, *]] {
       type F[x] = Nested[M, Validated[E, *], x]

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

@@ -9,11 +9,11 @@ import scala.collection.immutable.SortedMap
 trait SortedMapInstances extends SortedMapInstances2 {
 
   @deprecated("2.0.0-RC2", "Use cats.kernel.instances.sortedMap.catsKernelStdHashForSortedMap")
-  private[instances] def catsStdHashForSortedMap[K: Hash: Order, V: Hash]: Hash[SortedMap[K, V]] =
+  def catsStdHashForSortedMap[K: Hash: Order, V: Hash]: Hash[SortedMap[K, V]] =
     cats.kernel.instances.sortedMap.catsKernelStdHashForSortedMap[K, V]
 
   @deprecated("2.0.0-RC2", "Use cats.kernel.instances.sortedMap.catsKernelStdCommutativeMonoidForSortedMap")
-  private[instances] def catsStdCommutativeMonoidForSortedMap[K: Order, V: CommutativeSemigroup] =
+  def catsStdCommutativeMonoidForSortedMap[K: Order, V: CommutativeSemigroup] =
     cats.kernel.instances.sortedMap.catsKernelStdCommutativeMonoidForSortedMap[K, V]
 
   implicit def catsStdShowForSortedMap[A: Order, B](implicit showA: Show[A], showB: Show[B]): Show[SortedMap[A, B]] =
@@ -115,13 +115,13 @@ trait SortedMapInstances extends SortedMapInstances2 {
 
 private[instances] trait SortedMapInstances1 {
   @deprecated("2.0.0-RC2", "Use cats.kernel.instances.sortedMap.catsKernelStdEqForSortedMap")
-  private[instances] def catsStdEqForSortedMap[K: Order, V: Eq]: Eq[SortedMap[K, V]] =
+  def catsStdEqForSortedMap[K: Order, V: Eq]: Eq[SortedMap[K, V]] =
     new SortedMapEq[K, V]
 }
 
 private[instances] trait SortedMapInstances2 extends SortedMapInstances1 {
   @deprecated("2.0.0-RC2", "Use cats.kernel.instances.sortedMap.catsKernelStdMonoidForSortedMap")
-  private[instances] def catsStdMonoidForSortedMap[K: Order, V: Semigroup]: Monoid[SortedMap[K, V]] =
+  def catsStdMonoidForSortedMap[K: Order, V: Semigroup]: Monoid[SortedMap[K, V]] =
     new SortedMapMonoid[K, V]
 }
 

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

@@ -76,7 +76,7 @@ private[instances] trait SortedSetInstances1 {
     cats.kernel.instances.sortedSet.catsKernelStdHashForSortedSet[A]
 
   @deprecated("2.0.0-RC2", "Use cats.kernel.instances.sortedSet.catsKernelStdSemilatticeForSortedSet")
-  private[instances] def catsKernelStdSemilatticeForSortedSet[A: Order]: BoundedSemilattice[SortedSet[A]] =
+  def catsKernelStdSemilatticeForSortedSet[A: Order]: BoundedSemilattice[SortedSet[A]] =
     cats.kernel.instances.sortedSet.catsKernelStdBoundedSemilatticeForSortedSet[A]
 }
 

docs/src/main/tut/typeclasses/comonad.md

@@ -9,7 +9,7 @@ scaladoc: "#cats.Comonad"
 
 `Comonad` is a `Functor` and provides duals of the [`Monad`](monad.html) `pure`
 and `flatMap` functions.  A dual to a function has the same types but the 
-direction of the arrows are reversed. Whether or not that is useful even possible 
+direction of the arrows are reversed. Whether or not that is useful, or even possible, 
 depends on the particular type. For a more formal definition of duality, please 
 refer to [https://ncatlab.org/nlab/show/duality](https://ncatlab.org/nlab/show/duality).
 

docs/src/main/tut/typeclasses/lawtesting.md

@@ -82,14 +82,14 @@ object arbitraries {
 Now we can convert these `ScalaCheck` `Properties` into tests that the test framework can run.  [discipline](https://github.com/typelevel/discipline) provides a helper `checkAll` function that performs
 this conversion for two test frameworks: `ScalaTest` and `Specs2`.
 
-* If you are using `Specs2`, extend your test class with `org.typelevel.discipline.specs2.Discipline`.
+* If you are using `Specs2`, extend your test class with `org.typelevel.discipline.specs2.Discipline` (provided by `discipline-specs2`).
 
-* If you are using `ScalaTest`, extend your test class with `org.typelevel.discipline.scalatest.Discipline` and `org.scalatest.funsuite.AnyFunSuiteLike`.
+* If you are using `ScalaTest`, extend your test class with `org.typelevel.discipline.scalatest.Discipline` (provided by `discipline-scalatest`) and `org.scalatest.funsuite.AnyFunSuiteLike`.
 
 * For other test frameworks, you need to resort to their integration with `ScalaCheck` to test
-the `ScalaCheck` `Properties` provided by cats-laws.
+the `ScalaCheck` `Properties` provided by `cats-laws`.
 
-The following example is for ScalaTest.  If not using 
+The following example is for ScalaTest.
 
 ```tut:book
 import cats.implicits._
@@ -109,8 +109,8 @@ class TreeLawTests extends AnyFunSuite with Discipline {
 * `Discipline` provides `checkAll`, and must be mixed into `AnyFunSuite`
 * `arbitraries._` imports the `Arbitrary[Tree[_]]` instances needed to check the laws.
 
-Alternatively, you can use the `CatsSuite` provided by [Cats-testkit-scalatest](https://github.com/typelevel/cats-testkit-scalatest), 
-which is the same `CatsSuite` used in Cats to test all instances.  
+Alternatively, you can use the `CatsSuite` provided by [Cats-testkit-scalatest](https://github.com/typelevel/cats-testkit-scalatest),
+which is the same `CatsSuite` used in Cats to test all instances.
 
 Now when we run `test` in our sbt console, ScalaCheck will test if the `Functor` laws hold for our `Tree` type.
 You should see something like this:

docs/src/main/tut/typeclasses/semigroup.md

@@ -58,7 +58,7 @@ for `Map`s.
 ```tut:book:silent
 import cats.implicits._
 
-val map1 = Map("hello" -> 0, "world" -> 1)
+val map1 = Map("hello" -> 1, "world" -> 1)
 val map2 = Map("hello" -> 2, "cats"  -> 3)
 ```
 

docs/src/main/tut/typeclasses/traverse.md

@@ -160,6 +160,8 @@ def foldMap[F[_]: Traverse, A, B: Monoid](fa: F[A])(f: A => B): B =
   Traverse[F].traverse[Const[B, *], A, B](fa)(a => Const(f(a))).getConst
 ```
 
+This works because `Const[B, *]` is an `Applicative` if `B` is a `Monoid`, as explained in [the documentation of `Const`](const.html#example-2-traverse).
+
 ## Further Reading
 
 * [The Essence of the Iterator Pattern][iterator] - Gibbons, Oliveira. JFP 2009.