Scala 2.12.0-RC2

.travis.yml

@@ -8,8 +8,16 @@ git:
   depth: 9999
 
 scala:
-- 2.10.6
-- 2.11.8
+  - 2.10.6
+  - 2.11.8
+
+jdk:
+  - oraclejdk7
+
+matrix:
+  include:
+  - scala: 2.12.0-RC2
+    jdk: oraclejdk8
 
 before_install:
  - export PATH=${PATH}:./vendor/bundle

build.sbt

@@ -1,37 +1,21 @@
 import com.typesafe.sbt.SbtGhPages.GhPagesKeys._
 import sbtunidoc.Plugin.UnidocKeys._
 import ReleaseTransformations._
-import ScoverageSbtPlugin._
 import scala.xml.transform.{RewriteRule, RuleTransformer}
+import org.scalajs.sbtplugin.cross.CrossProject
 
 lazy val botBuild = settingKey[Boolean]("Build by TravisCI instead of local dev environment")
 
 lazy val scoverageSettings = Seq(
-  ScoverageKeys.coverageMinimum := 60,
-  ScoverageKeys.coverageFailOnMinimum := false,
-  ScoverageKeys.coverageHighlighting := scalaBinaryVersion.value != "2.10",
-  ScoverageKeys.coverageExcludedPackages := "cats\\.bench\\..*",
-  // don't include scoverage as a dependency in the pom
-  // see issue #980
-  // this code was copied from https://github.com/mongodb/mongo-spark
-  pomPostProcess := { (node: xml.Node) =>
-    new RuleTransformer(
-      new RewriteRule {
-        override def transform(node: xml.Node): Seq[xml.Node] = node match {
-          case e: xml.Elem
-              if e.label == "dependency" && e.child.exists(child => child.label == "groupId" && child.text == "org.scoverage") => Nil
-          case _ => Seq(node)
-
-        }
-
-      }).transform(node).head
-  }
+  coverageMinimum := 60,
+  coverageFailOnMinimum := false,
+  coverageHighlighting := scalaBinaryVersion.value != "2.10"
 )
 
 lazy val buildSettings = Seq(
   organization := "org.typelevel",
   scalaVersion := "2.11.8",
-  crossScalaVersions := Seq("2.10.6", "2.11.8")
+  crossScalaVersions := Seq("2.10.6", "2.11.8", "2.12.0-RC2")
 )
 
 lazy val catsDoctestSettings = Seq(
@@ -46,7 +30,7 @@ lazy val kernelSettings = Seq(
     Resolver.sonatypeRepo("snapshots")),
   parallelExecution in Test := false,
   scalacOptions in (Compile, doc) := (scalacOptions in (Compile, doc)).value.filter(_ != "-Xfatal-warnings")
-) ++ warnUnusedImport
+) ++ warnUnusedImport ++ update2_12
 
 lazy val commonSettings = Seq(
   incOptions := incOptions.value.withLogRecompileOnMacro(false),
@@ -57,17 +41,17 @@ lazy val commonSettings = Seq(
     Resolver.sonatypeRepo("snapshots")
   ),
   libraryDependencies ++= Seq(
-    "com.github.mpilquist" %%% "simulacrum" % "0.8.0",
-    "org.typelevel" %%% "machinist" % "0.4.1",
+    "com.github.mpilquist" %%% "simulacrum" % "0.10.0",
+    "org.typelevel" %%% "machinist" % "0.6.0",
     compilerPlugin("org.scalamacros" %% "paradise" % "2.1.0" cross CrossVersion.full),
-    compilerPlugin("org.spire-math" %% "kind-projector" % "0.9.0")
+    compilerPlugin("org.spire-math" %% "kind-projector" % "0.9.2")
   ),
   fork in test := true,
   parallelExecution in Test := false,
   scalacOptions in (Compile, doc) := (scalacOptions in (Compile, doc)).value.filter(_ != "-Xfatal-warnings"),
   // workaround for https://github.com/scalastyle/scalastyle-sbt-plugin/issues/47
-  (scalastyleSources in Compile) <++= unmanagedSourceDirectories in Compile
-) ++ warnUnusedImport
+  scalastyleSources in Compile ++= (unmanagedSourceDirectories in Compile).value
+) ++ warnUnusedImport ++ update2_12
 
 lazy val tagName = Def.setting{
  s"v${if (releaseUseGlobalVersion.value) (version in ThisBuild).value else version.value}"
@@ -84,8 +68,6 @@ lazy val commonJsSettings = Seq(
   },
   scalaJSStage in Global := FastOptStage,
   parallelExecution := false,
-  // Using Rhino as jsEnv to build scala.js code can lead to OOM, switch to PhantomJS by default
-  scalaJSUseRhino := false,
   requiresDOM := false,
   jsEnv := NodeJSEnv().value,
   // Only used for scala.js for now
@@ -115,15 +97,15 @@ lazy val catsSettings = buildSettings ++ commonSettings ++ publishSettings ++ sc
 
 lazy val scalaCheckVersion = "1.13.2"
 lazy val scalaTestVersion = "3.0.0"
-lazy val disciplineVersion = "0.6"
+lazy val disciplineVersion = "0.7.1"
 
 lazy val disciplineDependencies = Seq(
   libraryDependencies += "org.scalacheck" %%% "scalacheck" % scalaCheckVersion,
   libraryDependencies += "org.typelevel" %%% "discipline" % disciplineVersion)
 
 lazy val testingDependencies = Seq(
-  libraryDependencies += "org.typelevel" %%% "catalysts-platform" % "0.0.2",
-  libraryDependencies += "org.typelevel" %%% "catalysts-macros" % "0.0.2" % "test",
+  libraryDependencies += "org.typelevel" %%% "catalysts-platform" % "0.0.4",
+  libraryDependencies += "org.typelevel" %%% "catalysts-macros" % "0.0.4" % "test",
   libraryDependencies += "org.scalatest" %%% "scalatest" % scalaTestVersion % "test")
 
 
@@ -224,6 +206,7 @@ lazy val macros = crossProject.crossType(CrossType.Pure)
   .settings(catsSettings:_*)
   .jsSettings(commonJsSettings:_*)
   .jvmSettings(commonJvmSettings:_*)
+  .jsSettings(coverageEnabled := false)
   .settings(scalacOptions := scalacOptions.value.filter(_ != "-Xfatal-warnings"))
 
 lazy val macrosJVM = macros.jvm
@@ -236,7 +219,7 @@ lazy val kernel = crossProject.crossType(CrossType.Pure)
   .settings(buildSettings: _*)
   .settings(publishSettings: _*)
   .settings(scoverageSettings: _*)
-  .settings(sourceGenerators in Compile <+= (sourceManaged in Compile).map(KernelBoiler.gen))
+  .settings(sourceGenerators in Compile += (sourceManaged in Compile).map(KernelBoiler.gen).taskValue)
   .settings(includeGeneratedSrc)
   .jsSettings(commonJsSettings:_*)
   .jvmSettings((commonJvmSettings ++ (mimaPreviousArtifacts := Set("org.typelevel" %% "cats-kernel" % "0.7.0"))):_*)
@@ -255,6 +238,7 @@ lazy val kernelLaws = crossProject.crossType(CrossType.Pure)
   .settings(testingDependencies: _*)
   .jsSettings(commonJsSettings:_*)
   .jvmSettings(commonJvmSettings:_*)
+  .jsSettings(coverageEnabled := false)
   .dependsOn(kernel)
 
 lazy val kernelLawsJVM = kernelLaws.jvm
@@ -264,8 +248,10 @@ lazy val core = crossProject.crossType(CrossType.Pure)
   .dependsOn(macros, kernel)
   .settings(moduleName := "cats-core")
   .settings(catsSettings:_*)
-  .settings(sourceGenerators in Compile <+= (sourceManaged in Compile).map(Boilerplate.gen))
+  .settings(sourceGenerators in Compile += (sourceManaged in Compile).map(Boilerplate.gen).taskValue)
   .settings(includeGeneratedSrc)
+  .configureCross(disableScoverage210Jvm)
+  .configureCross(disableScoverage210Js)
   .settings(libraryDependencies += "org.scalacheck" %%% "scalacheck" % scalaCheckVersion % "test")
   .jsSettings(commonJsSettings:_*)
   .jvmSettings(commonJvmSettings:_*)
@@ -278,9 +264,10 @@ lazy val laws = crossProject.crossType(CrossType.Pure)
   .settings(moduleName := "cats-laws")
   .settings(catsSettings:_*)
   .settings(disciplineDependencies:_*)
-  .settings(libraryDependencies ++= Seq("org.typelevel" %%% "catalysts-platform" % "0.0.2"))
+  .settings(libraryDependencies ++= Seq("org.typelevel" %%% "catalysts-platform" % "0.0.4"))
   .jsSettings(commonJsSettings:_*)
   .jvmSettings(commonJvmSettings:_*)
+  .jsSettings(coverageEnabled := false)
 
 lazy val lawsJVM = laws.jvm
 lazy val lawsJS = laws.js
@@ -309,13 +296,15 @@ lazy val testsJVM = tests.jvm
 lazy val testsJS = tests.js
 
 // bench is currently JVM-only
+
 lazy val bench = project.dependsOn(macrosJVM, coreJVM, freeJVM, lawsJVM)
   .settings(moduleName := "cats-bench")
   .settings(catsSettings)
   .settings(noPublishSettings)
   .settings(commonJvmSettings)
+  .settings(coverageEnabled := false)
   .settings(libraryDependencies ++= Seq(
-    "org.scalaz" %% "scalaz-core" % "7.2.5"))
+    "org.scalaz" %% "scalaz-core" % "7.2.6"))
   .enablePlugins(JmhPlugin)
 
 // cats-js is JS-only
@@ -324,6 +313,7 @@ lazy val js = project
   .settings(moduleName := "cats-js")
   .settings(catsSettings:_*)
   .settings(commonJsSettings:_*)
+  .configure(disableScoverage210Js)
   .enablePlugins(ScalaJSPlugin)
 
 
@@ -461,8 +451,8 @@ lazy val scalaMacroDependencies: Seq[Setting[_]] = Seq(
       // in Scala 2.10, quasiquotes are provided by macro paradise
       case Some((2, 10)) =>
         Seq(
-          compilerPlugin("org.scalamacros" %% "paradise" % "2.0.1" cross CrossVersion.full),
-              "org.scalamacros" %% "quasiquotes" % "2.0.1" cross CrossVersion.binary
+          compilerPlugin("org.scalamacros" %% "paradise" % "2.1.0" cross CrossVersion.full),
+              "org.scalamacros" %% "quasiquotes" % "2.1.0" cross CrossVersion.binary
         )
     }
   }
@@ -479,7 +469,6 @@ lazy val commonScalacOptions = Seq(
   "-unchecked",
   "-Xfatal-warnings",
   "-Xlint",
-  "-Yinline-warnings",
   "-Yno-adapted-args",
   "-Ywarn-dead-code",
   "-Ywarn-numeric-widen",
@@ -529,7 +518,7 @@ lazy val warnUnusedImport = Seq(
     }
   },
   scalacOptions in (Compile, console) ~= {_.filterNot("-Ywarn-unused-import" == _)},
-  scalacOptions in (Test, console) <<= (scalacOptions in (Compile, console))
+  scalacOptions in (Test, console) := (scalacOptions in (Compile, console)).value
 )
 
 lazy val credentialSettings = Seq(
@@ -539,3 +528,45 @@ lazy val credentialSettings = Seq(
     password <- Option(System.getenv().get("SONATYPE_PASSWORD"))
   } yield Credentials("Sonatype Nexus Repository Manager", "oss.sonatype.org", username, password)).toSeq
 )
+
+def disableScoverage210Js(crossProject: CrossProject) =
+  crossProject
+  .jsSettings(
+    coverageEnabled := {
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, 10)) => false
+        case _ => coverageEnabled.value
+      }
+    }
+  )
+
+def disableScoverage210Js: Project ⇒ Project = p =>
+  p.settings(
+    coverageEnabled := {
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, 10)) => false
+        case _ => coverageEnabled.value
+      }
+    }
+  )
+
+def disableScoverage210Jvm(crossProject: CrossProject) =
+  crossProject
+  .jvmSettings(
+    coverageEnabled := {
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, 10)) => false
+        case _ => coverageEnabled.value
+      }
+    }
+  )
+
+lazy val update2_12 = Seq(
+  scalacOptions -= {
+    CrossVersion.partialVersion(scalaVersion.value) match {
+      case Some((2, 12)) => "-Yinline-warnings"
+      case _ => ""
+    }
+  }
+)
+

core/src/main/scala/cats/Eval.scala

@@ -74,8 +74,11 @@ sealed abstract class Eval[+A] extends Serializable { self =>
       case c: Eval.Compute[A] =>
         new Eval.Compute[B] {
           type Start = c.Start
-          val start = c.start
-          val run = (s: c.Start) =>
+          // See https://issues.scala-lang.org/browse/SI-9931 for an explanation
+          // of why the type annotations are necessary in these two lines on
+          // Scala 2.12.0.
+          val start: () => Eval[Start] = c.start
+          val run: Start => Eval[B] = (s: c.Start) =>
             new Eval.Compute[B] {
               type Start = A
               val start = () => c.run(s)

docs/src/main/tut/datatypes/either.md

@@ -235,16 +235,30 @@ object Service {
 Let's say we have an application that wants to do database things, and then take database
 values and do service things. Glancing at the types, it looks like `flatMap` will do it.
 
-```tut:fail:silent
+```scala
 def doApp = Database.databaseThings().flatMap(Service.serviceThings)
 ```
 
-This doesn't work! The reason this occurs is because the first type parameter in the two `Either`s are different -
-`databaseThings()` can give us a `DatabaseError` whereas `serviceThings()` can give us a
-`ServiceError`: two completely unrelated types. While `Either`'s type parameters are covariant,
-the aforementioned syntax enrichment is invariant to avoid nasty variance issues like inferring
-`Object`. Therefore, when the compiler sees `Either[E1, A1]` and an `Either[E2, A2]`, it
-will simply reject the `flatMap` call.
+If you're on Scala 2.12, this line will compile and work as expected, but if you're on an earlier
+version of Scala it won't! This difference is related to the right-biasing of `Either` in Scala 2.12
+that was mentioned above. In Scala 2.12 the `flatMap` we get here is a method on `Either` with this
+signature:
+
+```scala
+def flatMap[AA >: A, Y](f: (B) => Either[AA, Y]): Either[AA, Y]
+```
+
+This `flatMap` is different from the ones you'll find on `List` or `Option`, for example, in that it
+has two type parameters, with the extra `AA` parameter allowing us to `flatMap` into an `Either`
+with a different type on the left side.
+
+This behavior is consistent with the covariance of `Either`, and in some cases it can be convenient,
+but it also makes it easy to run into nasty variance issues (such as `Object` being inferred as the
+type of the left side, as it is in this case).
+
+For this reason the `flatMap` provided by Cats's `Either` syntax (which is the one you'll get for
+Scala 2.10 and 2.11) does not include this extra type parameter. Instead the left sides have to
+match, which means our `doApp` definition above will not compile on versions of Scala before 2.12.
 
 ### Solution 1: Application-wide errors
 So clearly in order for us to easily compose `Either` values, the left type parameter must be the same.

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

@@ -10,6 +10,7 @@ import org.typelevel.discipline.{ Laws }
 import org.typelevel.discipline.scalatest.Discipline
 import org.scalacheck.{ Arbitrary, Cogen, Gen }
 import Arbitrary.arbitrary
+import org.scalactic.anyvals.{ PosInt, PosZInt }
 import org.scalatest.FunSuite
 
 import scala.util.Random
@@ -18,11 +19,11 @@ import scala.collection.immutable.BitSet
 class LawTests extends FunSuite with Discipline {
 
   // The scalacheck defaults (100,100) are too high for scala-js.
-  final val PropMaxSize = if (Platform.isJs) 10 else 100
-  final val PropMinSuccessful = if (Platform.isJs) 10 else 100
+  final val PropMaxSize: PosZInt = if (Platform.isJs) 10 else 100
+  final val PropMinSuccessful: PosInt = if (Platform.isJs) 10 else 100
 
   implicit override val generatorDrivenConfig: PropertyCheckConfiguration =
-    PropertyCheckConfig(maxSize = PropMaxSize, minSuccessful = PropMinSuccessful)
+    PropertyCheckConfiguration(minSuccessful = PropMinSuccessful, sizeRange = PropMaxSize)
 
   implicit def orderLaws[A: Cogen: Eq: Arbitrary]: OrderLaws[A] = OrderLaws[A]
   implicit def groupLaws[A: Cogen: Eq: Arbitrary]: GroupLaws[A] = GroupLaws[A]

project/build.properties

@@ -1 +1 @@
-sbt.version=0.13.12
+sbt.version=0.13.13-RC3

project/plugins.sbt

@@ -1,13 +1,13 @@
 addSbtPlugin("com.eed3si9n"         % "sbt-unidoc"            % "0.3.3")
 addSbtPlugin("com.github.gseitz"    % "sbt-release"           % "1.0.3")
 addSbtPlugin("com.jsuereth"         % "sbt-pgp"               % "1.0.0")
-addSbtPlugin("com.typesafe"         % "sbt-mima-plugin"       % "0.1.9")
+addSbtPlugin("com.typesafe"         % "sbt-mima-plugin"       % "0.1.11")
 addSbtPlugin("com.typesafe.sbt"     % "sbt-ghpages"           % "0.5.3")
-addSbtPlugin("pl.project13.scala"   % "sbt-jmh"               % "0.2.11")
+addSbtPlugin("pl.project13.scala"   % "sbt-jmh"               % "0.2.16")
 addSbtPlugin("org.scalastyle"      %% "scalastyle-sbt-plugin" % "0.8.0")
-addSbtPlugin("org.scoverage"        % "sbt-scoverage"         % "1.2.0")
+addSbtPlugin("org.scoverage"        % "sbt-scoverage"         % "1.5.0-RC2")
 addSbtPlugin("com.typesafe.sbt"     % "sbt-git"               % "0.8.5")
-addSbtPlugin("org.scala-js"         % "sbt-scalajs"           % "0.6.11")
+addSbtPlugin("org.scala-js"         % "sbt-scalajs"           % "0.6.13")
 addSbtPlugin("com.github.tkawachi"  % "sbt-doctest"           % "0.4.1")
 addSbtPlugin("org.xerial.sbt"       % "sbt-sonatype"          %  "1.1")
-addSbtPlugin("com.fortysevendeg"    % "sbt-microsites"        % "0.2.6")
+addSbtPlugin("com.fortysevendeg"    % "sbt-microsites"        % "0.2.7")

tests/src/test/scala/cats/tests/CatsSuite.scala

@@ -23,7 +23,7 @@ trait TestSettings extends Configuration with Matchers {
 
   lazy val slowCheckConfiguration: PropertyCheckConfiguration =
     if (Platform.isJvm) checkConfiguration
-    else PropertyCheckConfig(maxSize = 1, minSuccessful = 1)
+    else PropertyCheckConfiguration(minSuccessful = 1, sizeRange = 1)
 }
 
 /**

tests/src/test/scala/cats/tests/NestedTests.scala

@@ -13,7 +13,7 @@ class NestedTests extends CatsSuite {
   // Scalacheck to calm down a bit so we don't hit memory and test duration
   // issues.
   implicit override val generatorDrivenConfig: PropertyCheckConfiguration =
-    PropertyCheckConfig(maxSize = 5, minSuccessful = 20)
+    PropertyCheckConfiguration(minSuccessful = 20, sizeRange = 5)
 
   implicit val iso = {
     implicit val instance = ListWrapper.functor

tests/src/test/scala/cats/tests/NonEmptyListTests.scala

@@ -10,7 +10,7 @@ import cats.laws.discipline.arbitrary._
 class NonEmptyListTests extends CatsSuite {
   // Lots of collections here.. telling ScalaCheck to calm down a bit
   implicit override val generatorDrivenConfig: PropertyCheckConfiguration =
-    PropertyCheckConfig(maxSize = 5, minSuccessful = 20)
+    PropertyCheckConfiguration(minSuccessful = 20, sizeRange = 5)
 
   checkAll("NonEmptyList[Int]", OrderLaws[NonEmptyList[Int]].order)