EpamLifeSciencesTeam · Twizty · Apr 23, 2018 · Aug 10, 2018 · Sep 30, 2018 · Mar 4, 2019
diff --git a/AUTHORS.md b/AUTHORS.md
@@ -40,6 +40,7 @@ possible:
  * Arya Irani
  * Ash Pook
  * Aλ
+ * Barnabás Oláh
  * Ben Fradet
  * Ben Hutchison
  * Ben Kirwin
@@ -79,6 +80,7 @@ possible:
  * Denis
  * Derek Wickern
  * Diego Esteban Alonso Blas
+ * Dmitry Polienko
  * Donaldo Salas
  * Earl St Sauver
  * Edd Steel
@@ -104,10 +106,12 @@ possible:
  * Gabriele Petronella
  * Gagandeep Kalra
  * Gavin Bisesi
+ * Georgi Krastev
  * Giovanni Ruggiero
  * Giulio De Luise
  * Giuseppe Cannella
  * Greg Pfeil
+ * Gregor Heine
  * Guillaume Massé
  * Hamed Nourhani
  * Hamish Dickson
@@ -151,10 +155,12 @@ possible:
  * Lars Hupel
  * Leandro Bolivar
  * Leif Battermann
+ * Lionel Parreaux
  * Long Cao
  * Luis Angel Vicente Sanchez
  * Luis Sanchez
  * Luka Jacobowitz
+ * Lukáš Voda
  * Luke Wyman
  * Madder
  * Marc Siegel
@@ -169,11 +175,13 @@ possible:
  * Matt Martin
  * Matthias Lüneberg
  * Max Worgan
+ * Maxim Davydov
  * Merlin Göttlinger
  * Michał Gutowski
  * Michael Ledin
  * Michael Pilquist
  * Mike Curry
+ * Miklós Martin
  * Miles Sabin
  * Mirco Dotta
  * nigredo-tori
@@ -210,6 +218,7 @@ possible:
  * Rob Norris
  * Rohan Shah
  * Romain Ruetschi
+ * Roman Tkalenko
  * Ross A. Baker
  * rsekulski
  * rsoeldner
@@ -228,6 +237,7 @@ possible:
  * Stephen Carman
  * Stephen Judkins
  * Stephen Lazaro
+ * Steven Scott
  * Suhas Gaddam
  * sullis
  * Sumedh Mungee

diff --git a/CHANGES.md b/CHANGES.md
@@ -1,3 +1,100 @@
+## Version 2.1.0-RC1
+
+_2019 November 15_
+
+This release is currently only available for Scala 2.11 and Scala 2.12. It provides the same binary compatibility guarantees as Cats 2.0 (and is verified by MiMa to be fully binary-compatible with 2.0 itself).
+
+### 2 source breaking changes
+
+* [#3154](https://github.com/typelevel/cats/pull/3154) Make 1.x deprecation targets package-private  by @travisbrown
+* [#3099](https://github.com/typelevel/cats/pull/3099) Issue 3059: Move Parallel instances into instance packages for the type constructors they characterize  by @barambani
+
+
+### 3 bug fixes
+
+* [#3126](https://github.com/typelevel/cats/pull/3126) Remove Order constraint from Hash instance for Map  by @vasiliybondarenko
+* [#3105](https://github.com/typelevel/cats/pull/3105) Issue 2701 - Ambiguous Eq instances for tuples  by @barambani
+* [#3100](https://github.com/typelevel/cats/pull/3100) Issue 2891 - Ambiguous Vector instances  by @barambani
+
+
+### 25 API / feature enhancements
+
+* [#3152](https://github.com/typelevel/cats/pull/3152) "Move" type class syntax methods onto type classes  by @travisbrown
+* [#3149](https://github.com/typelevel/cats/pull/3149) Deprecate and make private syntax methods that are now on Either  by @travisbrown
+* [#3148](https://github.com/typelevel/cats/pull/3148) Move adaptError  by @travisbrown
+* [#3147](https://github.com/typelevel/cats/pull/3147) Add Parallel.parFoldMapA  by @nigredo-tori
+* [#3146](https://github.com/typelevel/cats/pull/3146) Add redeem and redeemWith  by @travisbrown
+* [#3144](https://github.com/typelevel/cats/pull/3144) Add Align for Stream  by @travisbrown
+* [#3136](https://github.com/typelevel/cats/pull/3136) Add benchmark for foldMapA  by @travisbrown
+* [#3135](https://github.com/typelevel/cats/pull/3135) Minor clean up. Removed duplication.  by @barambani
+* [#3133](https://github.com/typelevel/cats/pull/3133) Fix NonEmptyChain.fromSeq signature on 2.12  by @travisbrown
+* [#3130](https://github.com/typelevel/cats/pull/3130) add foldMapA as an alternative to foldMapM that only requires an Applicative rather than a monad  by @mberndt123
+* [#3124](https://github.com/typelevel/cats/pull/3124) SemigroupK sum: F[A], F[B] => F[A Either B]  by @pk044
+* [#3122](https://github.com/typelevel/cats/pull/3122) Fix constraints and names for new Foldable methods  by @travisbrown
+* [#3103](https://github.com/typelevel/cats/pull/3103) Add TraverseFilter instance for Queue.  by @takayahilton
+* [#3088](https://github.com/typelevel/cats/pull/3088) #2947 Added bifold to Bifoldable typeclass  by @Twizty
+* [#3084](https://github.com/typelevel/cats/pull/3084) Add minimumBy/maximumBy/Option to Foldable  by @joroKr21
+* [#3076](https://github.com/typelevel/cats/pull/3076) Add Align typeclass  by @LukaJCB
+* [#3062](https://github.com/typelevel/cats/pull/3062) add unzip to Functor  by @gagandeepkalra
+* [#3058](https://github.com/typelevel/cats/pull/3058) Add `ifF` on Functor #3040  by @vasiliybondarenko
+* [#3041](https://github.com/typelevel/cats/pull/3041) Add scala.util.control.TailCalls.TailRec instances  by @johnynek
+* [#3015](https://github.com/typelevel/cats/pull/3015) Use Foldable foldRight for Traverse and TraverseFilter.  by @takayahilton
+* [#2863](https://github.com/typelevel/cats/pull/2863) add attemptNarrow to ApplicativeErrorOps  by @marcodippy
+* [#2834](https://github.com/typelevel/cats/pull/2834) CommutativeMonoid[Option[A]] from CommutativeSemigroup  by @valydia
+* [#2772](https://github.com/typelevel/cats/pull/2772) Add foldRightDefer to Foldable  by @denisrosca
+* [#2742](https://github.com/typelevel/cats/pull/2742) Added separateFoldable  by @tkroman
+* [#2380](https://github.com/typelevel/cats/pull/2380) Add combineAllOption to Foldable  by @barambani
+
+
+### 12 documentation improvements
+
+* [#3156](https://github.com/typelevel/cats/pull/3156) Fix link to Monad and Comonad  by @XeeD
+* [#3151](https://github.com/typelevel/cats/pull/3151) fix link to moniodK and Applicative  by @stsatlantis
+* [#3104](https://github.com/typelevel/cats/pull/3104) Update faq.md repl documentation  by @psilospore
+* [#3081](https://github.com/typelevel/cats/pull/3081) Correct some mistakes in Comonad documentatoin  by @justinhj
+* [#3073](https://github.com/typelevel/cats/pull/3073) add more doctest to WriterT  by @hamednourhani
+* [#3072](https://github.com/typelevel/cats/pull/3072) Mention additional dependencies in lawtesting docs  by @miklos-martin
+* [#3071](https://github.com/typelevel/cats/pull/3071) Update Semigroup docs for Map  by @codingismy11to7
+* [#3065](https://github.com/typelevel/cats/pull/3065) Link to relevant Const doc from doc of Traverse  by @LPTK
+* [#3063](https://github.com/typelevel/cats/pull/3063) add more doctest to Ior  by @hamednourhani
+* [#3061](https://github.com/typelevel/cats/pull/3061) Validated doctest  by @hamednourhani
+* [#3054](https://github.com/typelevel/cats/pull/3054) add more doctest to EitherT  by @hamednourhani
+* [#3049](https://github.com/typelevel/cats/pull/3049) minor update to the doc to include cats-testkit-scalatest  by @kailuowang
+
+
+### 29 build improvements
+
+* [#3142](https://github.com/typelevel/cats/pull/3142) Backport MiMa config and dependency updates for 2.11  by @travisbrown
+* [#3139](https://github.com/typelevel/cats/pull/3139) Update 2.11 branch build  by @travisbrown
+* [#3129](https://github.com/typelevel/cats/pull/3129) Check bincompat on stuff we should be checking bincompat for  by @travisbrown
+* [#3125](https://github.com/typelevel/cats/pull/3125) Fix order of @deprecated arguments  by @travisbrown
+* [#3120](https://github.com/typelevel/cats/pull/3120) Update sbt-scalafmt to 2.2.1  by @scala-steward
+* [#3118](https://github.com/typelevel/cats/pull/3118) Update sbt-scalafmt to 2.2.0  by @scala-steward
+* [#3115](https://github.com/typelevel/cats/pull/3115) Update sbt-release to 1.0.12  by @scala-steward
+* [#3114](https://github.com/typelevel/cats/pull/3114) Update sbt to 1.3.3  by @scala-steward
+* [#3110](https://github.com/typelevel/cats/pull/3110) Update sbt-scalafmt to 2.0.7  by @scala-steward
+* [#3106](https://github.com/typelevel/cats/pull/3106) ci: Enable 2.13 build for scalajs and linting in travis  by @DieBauer
+* [#3102](https://github.com/typelevel/cats/pull/3102) Use new group ID for simulacrum  by @travisbrown
+* [#3101](https://github.com/typelevel/cats/pull/3101) update ScalaTest  by @larsrh
+* [#3096](https://github.com/typelevel/cats/pull/3096) Enable coverage and docs  by @DieBauer
+* [#3095](https://github.com/typelevel/cats/pull/3095) Update sbt-microsites to 0.9.7  by @scala-steward
+* [#3094](https://github.com/typelevel/cats/pull/3094) Update tut-plugin to 0.6.13  by @scala-steward
+* [#3092](https://github.com/typelevel/cats/pull/3092) Update scalafmt-core to 2.1.0  by @scala-steward
+* [#3091](https://github.com/typelevel/cats/pull/3091) Update sbt-sonatype to 3.8  by @scala-steward
+* [#3090](https://github.com/typelevel/cats/pull/3090) Update sbt-scalafmt to 2.0.6  by @scala-steward
+* [#3089](https://github.com/typelevel/cats/pull/3089) Update scalacheck to 1.14.2  by @scala-steward
+* [#3086](https://github.com/typelevel/cats/pull/3086) Update simulacrum to 1.0.0  by @scala-steward
+* [#3085](https://github.com/typelevel/cats/pull/3085) Update sbt-microsites to 0.9.6  by @scala-steward
+* [#3079](https://github.com/typelevel/cats/pull/3079) update to sbt 1.3.x, uses coursier by default  by @larsrh
+* [#3070](https://github.com/typelevel/cats/pull/3070) Update sbt-scalajs, scalajs-compiler to 0.6.29  by @scala-steward
+* [#3066](https://github.com/typelevel/cats/pull/3066) Update sbt-scalafmt to 2.0.5  by @scala-steward
+* [#3064](https://github.com/typelevel/cats/pull/3064) Update sbt-pgp to 2.0.1-M3  by @scala-steward
+* [#3056](https://github.com/typelevel/cats/pull/3056) Update sbt-sonatype to 3.7  by @scala-steward
+* [#3052](https://github.com/typelevel/cats/pull/3052) Create a Scala 2.11 branch  by @kailuowang
+* [#3051](https://github.com/typelevel/cats/pull/3051) Drops Scala 2.11 support on master  by @kailuowang
+* [#3030](https://github.com/typelevel/cats/pull/3030) Update sbt-sonatype to 3.6  by @scala-steward
+
+
 ## Version 2.0.0
 
 > 2019 September 9

diff --git a/README.md b/README.md
@@ -1,5 +1,6 @@
 
 ### ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) Community Announcements ![#f03c15](https://placehold.it/15/f03c15/000000?text=+)
+* **Nov 15 2019** [Cats 2.1.0-RC1 is released](https://github.com/typelevel/cats/releases/tag/v2.1.0-RC1)
 * **Sep 9 2019** [Cats 2.0.0 is released](https://github.com/typelevel/cats/releases/tag/v2.0.0)
 * **Sep 7 2019** [Cats 2.0.0-RC3 is released](https://github.com/typelevel/cats/releases/tag/v2.0.0-RC3)
 * **Aug 26 2019** [Cats 2.0.0-RC2 is released](https://github.com/typelevel/cats/releases/tag/v2.0.0-RC2)

diff --git a/core/src/main/scala-2.12/cats/compat/FoldableCompat.scala b/core/src/main/scala-2.12/cats/compat/FoldableCompat.scala
@@ -0,0 +1,11 @@
+package cats
+package compat
+
+private[cats] object FoldableCompat {
+
+  def toIterable[F[_], A](fa: F[A])(F: Foldable[F]): Iterable[A] =
+    F.foldRight[A, Stream[A]](fa, Eval.now(Stream.empty)) { (a, eb) =>
+        eb.map(Stream.cons(a, _))
+      }
+      .value
+}
diff --git a/core/src/main/scala-2.12/cats/data/ScalaVersionSpecificNonEmptyChainImpl.scala b/core/src/main/scala-2.12/cats/data/ScalaVersionSpecificNonEmptyChainImpl.scala
@@ -0,0 +1,6 @@
+package cats.data
+
+private[data] trait ScalaVersionSpecificNonEmptyChainImpl {
+  def fromSeq[A](as: scala.collection.Seq[A]): Option[NonEmptyChain[A]] =
+    if (as.nonEmpty) Option(NonEmptyChainImpl.create(Chain.fromSeq(as))) else None
+}
diff --git a/core/src/main/scala-2.12/cats/instances/stream.scala b/core/src/main/scala-2.12/cats/instances/stream.scala
@@ -140,6 +140,8 @@ trait StreamInstances extends cats.kernel.instances.StreamInstances {
 
       override def toList[A](fa: Stream[A]): List[A] = fa.toList
 
+      override def toIterable[A](fa: Stream[A]): Iterable[A] = fa
+
       override def reduceLeftOption[A](fa: Stream[A])(f: (A, A) => A): Option[A] =
         fa.reduceLeftOption(f)
 

diff --git a/core/src/main/scala-2.13+/cats/compat/FoldableCompat.scala b/core/src/main/scala-2.13+/cats/compat/FoldableCompat.scala
@@ -0,0 +1,11 @@
+package cats
+package compat
+
+private[cats] object FoldableCompat {
+
+  def toIterable[F[_], A](fa: F[A])(F: Foldable[F]): Iterable[A] =
+    F.foldRight[A, LazyList[A]](fa, Eval.now(LazyList.empty)) { (a, eb) =>
+        eb.map(LazyList.cons(a, _))
+      }
+      .value
+}
diff --git a/core/src/main/scala-2.13+/cats/data/ScalaVersionSpecificNonEmptyChainImpl.scala b/core/src/main/scala-2.13+/cats/data/ScalaVersionSpecificNonEmptyChainImpl.scala
@@ -0,0 +1,3 @@
+package cats.data
+
+private[data] trait ScalaVersionSpecificNonEmptyChainImpl
diff --git a/core/src/main/scala-2.13+/cats/instances/lazyList.scala b/core/src/main/scala-2.13+/cats/instances/lazyList.scala
@@ -118,6 +118,8 @@ trait LazyListInstances extends cats.kernel.instances.LazyListInstances {
 
       override def toList[A](fa: LazyList[A]): List[A] = fa.toList
 
+      override def toIterable[A](fa: LazyList[A]): Iterable[A] = fa
+
       override def reduceLeftOption[A](fa: LazyList[A])(f: (A, A) => A): Option[A] =
         fa.reduceLeftOption(f)
 

diff --git a/core/src/main/scala-2.13+/cats/instances/stream.scala b/core/src/main/scala-2.13+/cats/instances/stream.scala
@@ -141,6 +141,8 @@ trait StreamInstances extends cats.kernel.instances.StreamInstances {
 
       override def toList[A](fa: Stream[A]): List[A] = fa.toList
 
+      override def toIterable[A](fa: Stream[A]): Iterable[A] = fa
+
       override def reduceLeftOption[A](fa: Stream[A])(f: (A, A) => A): Option[A] =
         fa.reduceLeftOption(f)
 

diff --git a/core/src/main/scala/cats/Alternative.scala b/core/src/main/scala/cats/Alternative.scala
@@ -41,6 +41,30 @@ import simulacrum.typeclass
     (as, bs)
   }
 
+  /**
+   * Separate the inner foldable values into the "lefts" and "rights".
+   * A variant of [[separate]] that is specialized
+   * for Fs that have Foldable instances
+   * which allows for a single-pass implementation
+   * (as opposed to {{{separate}}} which is 2-pass).
+   *
+   * Example:
+   * {{{
+   * scala> import cats.implicits._
+   * scala> val l: List[Either[String, Int]] = List(Right(1), Left("error"))
+   * scala> Alternative[List].separate(l)
+   * res0: (List[String], List[Int]) = (List(error),List(1))
+   * }}}
+   */
+  def separateFoldable[G[_, _], A, B](fgab: F[G[A, B]])(implicit G: Bifoldable[G], FF: Foldable[F]): (F[A], F[B]) =
+    FF.foldLeft(fgab, (empty[A], empty[B])) {
+      case (mamb, gab) =>
+        G.bifoldLeft(gab, mamb)(
+          (t, a) => (combineK(t._1, pure(a)), t._2),
+          (t, b) => (t._1, combineK(t._2, pure(b)))
+        )
+    }
+
   /**
    * Return ().pure[F] if `condition` is true, `empty` otherwise
    *

diff --git a/core/src/main/scala/cats/ApplicativeError.scala b/core/src/main/scala/cats/ApplicativeError.scala
@@ -1,6 +1,7 @@
 package cats
 
-import cats.data.EitherT
+import cats.data.{EitherT, Validated}
+import cats.data.Validated.{Invalid, Valid}
 
 import scala.reflect.ClassTag
 import scala.util.{Failure, Success, Try}
@@ -103,6 +104,65 @@ trait ApplicativeError[F[_], E] extends Applicative[F] {
   def recoverWith[A](fa: F[A])(pf: PartialFunction[E, F[A]]): F[A] =
     handleErrorWith(fa)(e => pf.applyOrElse(e, raiseError))
 
+  /**
+   * Transform certain errors using `pf` and rethrow them.
+   * Non matching errors and successful values are not affected by this function.
+   *
+   * Example:
+   * {{{
+   * scala> import cats._, implicits._
+   *
+   * scala> def pf: PartialFunction[String, String] = { case "error" => "ERROR" }
+   *
+   * scala> ApplicativeError[Either[String, *], String].adaptError("error".asLeft[Int])(pf)
+   * res0: Either[String,Int] = Left(ERROR)
+   *
+   * scala> ApplicativeError[Either[String, *], String].adaptError("err".asLeft[Int])(pf)
+   * res1: Either[String,Int] = Left(err)
+   *
+   * scala> ApplicativeError[Either[String, *], String].adaptError(1.asRight[String])(pf)
+   * res2: Either[String,Int] = Right(1)
+   * }}}
+   *
+   * The same function is available in `ApplicativeErrorOps` as `adaptErr` - it cannot have the same
+   * name because this would result in ambiguous implicits due to `adaptError`
+   * having originally been included in the `MonadError` API and syntax.
+   */
+  def adaptError[A](fa: F[A])(pf: PartialFunction[E, E]): F[A] =
+    recoverWith(fa)(pf.andThen(raiseError[A] _))
+
+  /**
+   * Returns a new value that transforms the result of the source,
+   * given the `recover` or `map` functions, which get executed depending
+   * on whether the result is successful or if it ends in error.
+   *
+   * This is an optimization on usage of [[attempt]] and [[map]],
+   * this equivalence being available:
+   *
+   * {{{
+   *   fa.redeem(fe, fs) <-> fa.attempt.map(_.fold(fe, fs))
+   * }}}
+   *
+   * Usage of `redeem` subsumes [[handleError]] because:
+   *
+   * {{{
+   *   fa.redeem(fe, id) <-> fa.handleError(fe)
+   * }}}
+   *
+   * Implementations are free to override it in order to optimize
+   * error recovery.
+   *
+   * @see [[MonadError.redeemWith]], [[attempt]] and [[handleError]]
+   *
+   * @param fa is the source whose result is going to get transformed
+   * @param recover is the function that gets called to recover the source
+   *        in case of error
+   * @param map is the function that gets to transform the source
+   *        in case of success
+   */
+  def redeem[A, B](fa: F[A])(recover: E => B, f: A => B): F[B] =
+    handleError(map(fa)(f))(recover)
+
   /**
    * Execute a callback on certain errors, then rethrow them.
    * Any non matching error is rethrown as well.
@@ -186,6 +246,48 @@ trait ApplicativeError[F[_], E] extends Applicative[F] {
       case Left(e)  => raiseError(e)
     }
 
+  /**
+   * Convert from scala.Option
+   *
+   * Example:
+   * {{{
+   * scala> import cats.implicits._
+   * scala> import cats.ApplicativeError
+   * scala> val F = ApplicativeError[Either[String, *], String]
+   *
+   * scala> F.fromOption(Some(1), "Empty")
+   * res0: scala.Either[String, Int] = Right(1)
+   *
+   * scala> F.fromOption(Option.empty[Int], "Empty")
+   * res1: scala.Either[String, Int] = Left(Empty)
+   * }}}
+   */
+  def fromOption[A](oa: Option[A], ifEmpty: => E): F[A] =
+    oa match {
+      case Some(a) => pure(a)
+      case None    => raiseError(ifEmpty)
+    }
+
+  /**
+   * Convert from cats.data.Validated
+   *
+   * Example:
+   * {{{
+   * scala> import cats.implicits._
+   * scala> import cats.ApplicativeError
+   *
+   * scala> ApplicativeError[Option, Unit].fromValidated(1.valid[Unit])
+   * res0: scala.Option[Int] = Some(1)
+   *
+   * scala> ApplicativeError[Option, Unit].fromValidated(().invalid[Int])
+   * res1: scala.Option[Int] = None
+   * }}}
+   */
+  def fromValidated[A](x: Validated[E, A]): F[A] =
+    x match {
+      case Invalid(e) => raiseError(e)
+      case Valid(a)   => pure(a)
+    }
 }
 
 object ApplicativeError {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		package cats.data

		private[data] trait ScalaVersionSpecificNonEmptyChainImpl