Cleanup ScalaStyle things

CONTRIBUTING.md

@@ -105,7 +105,7 @@ To build Cats you should have
  * `console`: launch a REPL
  * `test`: run the tests
  * `unidoc`: generate the documentation
- * `scalastyle`: run the style-checker on the code
+ * `fmt`: run formatting of the code
  * `validate`: run tests, style-checker, and doc generation
 
 #### Scala and Scala.js

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

@@ -146,7 +146,7 @@ final class Later[A](f: () => A) extends Eval.Leaf[A] {
   // expensive to store, consider using `Always`.)
   lazy val value: A = {
     val result = thunk()
-    thunk = null // scalastyle:off
+    thunk = null
     result
   }
 

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

@@ -22,7 +22,6 @@ sealed abstract class Chain[+A] {
     this match {
       case non: Chain.NonEmpty[A] =>
         var c: NonEmpty[A] = non
-        // scalastyle:off null
         var rights: Chain.NonEmpty[A] = null
         var result: (A, Chain[A]) = null
         while (result eq null) {
@@ -50,7 +49,6 @@ sealed abstract class Chain[+A] {
               result = (seq.head, next)
           }
         }
-        // scalastyle:on null
         Some(result)
       case _ => None
     }
@@ -62,7 +60,6 @@ sealed abstract class Chain[+A] {
     this match {
       case non: Chain.NonEmpty[A] =>
         var c: NonEmpty[A] = non
-        // scalastyle:off null
         var lefts: NonEmpty[A] = null
         var result: (Chain[A], A) = null
         while (result eq null) {
@@ -90,7 +87,6 @@ sealed abstract class Chain[+A] {
               result = (pre, seq.last)
           }
         }
-        // scalastyle:on null
         Some(result)
       case _ => None
     }
@@ -491,7 +487,6 @@ sealed abstract class Chain[+A] {
   /**
    * Applies the supplied function to each element, left to right, but stops when true is returned
    */
-  // scalastyle:off null return cyclomatic.complexity
   final private def foreachUntil(f: A => Boolean): Unit =
     this match {
       case non: Chain.NonEmpty[A] =>
@@ -531,7 +526,6 @@ sealed abstract class Chain[+A] {
         }
       case _ => ()
     }
-  // scalastyle:on null return cyclomatic.complexity
 
   final def iterator: Iterator[A] =
     this match {
@@ -599,9 +593,7 @@ sealed abstract class Chain[+A] {
       val iterX = iterator
       val iterY = that.iterator
       while (iterX.hasNext && iterY.hasNext) {
-        // scalastyle:off return
         if (!A.eqv(iterX.next(), iterY.next())) return false
-        // scalastyle:on return
       }
 
       iterX.hasNext == iterY.hasNext
@@ -877,7 +869,6 @@ object Chain extends ChainInstances {
       loop(0, as.size).value
     }
 
-  // scalastyle:off null
   private class ChainIterator[A](self: NonEmpty[A]) extends Iterator[A] {
     def this(chain: Chain[A]) =
       this(chain match {
@@ -930,9 +921,7 @@ object Chain extends ChainInstances {
       go
     }
   }
-  // scalastyle:on null
 
-  // scalastyle:off null
   private class ChainReverseIterator[A](self: NonEmpty[A]) extends Iterator[A] {
     def this(chain: Chain[A]) =
       this(chain match {
@@ -985,7 +974,6 @@ object Chain extends ChainInstances {
       go
     }
   }
-  // scalastyle:on null
 }
 
 sealed abstract private[data] class ChainInstances extends ChainInstances1 {
@@ -1109,9 +1097,7 @@ sealed abstract private[data] class ChainInstances extends ChainInstances1 {
           val iterY = y.iterator
           while (iterX.hasNext && iterY.hasNext) {
             val n = A0.compare(iterX.next(), iterY.next())
-            // scalastyle:off return
             if (n != 0) return n
-            // scalastyle:on return
           }
 
           if (iterX.hasNext) 1
@@ -1184,9 +1170,7 @@ private[data] trait ChainPartialOrder[A] extends PartialOrder[Chain[A]] {
       val iterY = y.iterator
       while (iterX.hasNext && iterY.hasNext) {
         val n = A.partialCompare(iterX.next(), iterY.next())
-        // scalastyle:off return
         if (n != 0.0) return n
-        // scalastyle:on return
       }
 
       if (iterX.hasNext) 1.0

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

@@ -730,7 +730,6 @@ sealed abstract class Ior[+A, +B] extends Product with Serializable {
    * res3: Ior[String, Int] = Both(abc,579)
    * }}}
    */
-  // scalastyle:off cyclomatic.complexity
   final def combine[AA >: A, BB >: B](that: AA Ior BB)(implicit AA: Semigroup[AA], BB: Semigroup[BB]): AA Ior BB =
     this match {
       case Ior.Left(a1) =>
@@ -752,7 +751,6 @@ sealed abstract class Ior[+A, +B] extends Product with Serializable {
           case Ior.Both(a2, b2) => Ior.Both(AA.combine(a1, a2), BB.combine(b1, b2))
         }
     }
-  // scalastyle:on cyclomatic.complexity
 
   final def ===[AA >: A, BB >: B](that: AA Ior BB)(implicit AA: Eq[AA], BB: Eq[BB]): Boolean =
     fold(
@@ -883,7 +881,6 @@ sealed abstract private[data] class IorInstances extends IorInstances0 {
       override def bimap[A, B, C, D](fab: A Ior B)(f: A => C, g: B => D): C Ior D = fab.bimap(f, g)
     }
 
-  // scalastyle:off cyclomatic.complexity
   implicit def catsDataParallelForIor[E](implicit E: Semigroup[E]): Parallel.Aux[Ior[E, *], Ior[E, *]] =
     new Parallel[Ior[E, *]] {
       type F[x] = Ior[E, x]
@@ -920,7 +917,6 @@ sealed abstract private[data] class IorInstances extends IorInstances0 {
 
       lazy val monad: Monad[Ior[E, *]] = Monad[Ior[E, *]]
     }
-  // scalastyle:on cyclomatic.complexity
 
 }
 

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

@@ -970,7 +970,6 @@ sealed abstract private[data] class ValidatedInstances2 {
       def eqv(x: Validated[A, B], y: Validated[A, B]): Boolean = x === y
     }
 
-  // scalastyle:off method.length
   implicit def catsDataTraverseFunctorForValidated[E]: Traverse[Validated[E, *]] =
     new Traverse[Validated[E, *]] {
 
@@ -1032,7 +1031,6 @@ sealed abstract private[data] class ValidatedInstances2 {
 
       override def isEmpty[A](fa: Validated[E, A]): Boolean = fa.isInvalid
     }
-  // scalastyle:off method.length
 }
 
 private[data] class ValidatedApplicative[E: Semigroup] extends CommutativeApplicative[Validated[E, *]] {

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

@@ -35,7 +35,6 @@ trait EitherInstances extends cats.kernel.instances.EitherInstances {
         }
     }
 
-  // scalastyle:off method.length
   implicit def catsStdInstancesForEither[A]
     : MonadError[Either[A, *], A] with Traverse[Either[A, *]] with Align[Either[A, *]] =
     new MonadError[Either[A, *], A] with Traverse[Either[A, *]] with Align[Either[A, *]] {
@@ -177,7 +176,6 @@ trait EitherInstances extends cats.kernel.instances.EitherInstances {
         }
 
     }
-  // scalastyle:on method.length
 
   implicit def catsStdSemigroupKForEither[L]: SemigroupK[Either[L, *]] =
     new SemigroupK[Either[L, *]] {

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

@@ -18,7 +18,6 @@ trait MapInstances extends cats.kernel.instances.MapInstances {
           .mkString("Map(", ", ", ")")
     }
 
-  // scalastyle:off method.length
   implicit def catsStdInstancesForMap[K]: UnorderedTraverse[Map[K, *]] with FlatMap[Map[K, *]] with Align[Map[K, *]] =
     new UnorderedTraverse[Map[K, *]] with FlatMap[Map[K, *]] with Align[Map[K, *]] {
 
@@ -110,7 +109,6 @@ trait MapInstances extends cats.kernel.instances.MapInstances {
           .result()
       }
     }
-  // scalastyle:on method.length
 
 }
 

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

@@ -27,7 +27,6 @@ trait SortedMapInstances extends SortedMapInstances2 {
   implicit def catsStdShowForSortedMap[A, B](orderA: Order[A], showA: Show[A], showB: Show[B]): Show[SortedMap[A, B]] =
     catsStdShowForSortedMap(showA, showB)
 
-  // scalastyle:off method.length
   implicit def catsStdInstancesForSortedMap[K]
     : Traverse[SortedMap[K, *]] with FlatMap[SortedMap[K, *]] with Align[SortedMap[K, *]] =
     new Traverse[SortedMap[K, *]] with FlatMap[SortedMap[K, *]] with Align[SortedMap[K, *]] {

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

@@ -9,7 +9,6 @@ import scala.annotation.tailrec
 
 trait TryInstances extends TryInstances1 {
 
-  // scalastyle:off method.length
   implicit def catsStdInstancesForTry: MonadThrow[Try] with CoflatMap[Try] with Traverse[Try] with Monad[Try] =
     new TryCoflatMap with MonadThrow[Try] with Traverse[Try] with Monad[Try] {
       def pure[A](x: A): Try[A] = Success(x)
@@ -143,7 +142,6 @@ trait TryInstances extends TryInstances1 {
 
       override def catchNonFatalEval[A](a: Eval[A])(implicit ev: Throwable <:< Throwable): Try[A] = Try(a.value)
     }
-  // scalastyle:on method.length
 
   implicit def catsStdShowForTry[A](implicit A: Show[A]): Show[Try[A]] =
     new Show[Try[A]] {

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

@@ -11,7 +11,7 @@ trait EitherSyntax {
   implicit final def catsSyntaxEither[A, B](eab: Either[A, B]): EitherOps[A, B] = new EitherOps(eab)
 
   implicit final def catsSyntaxEitherObject(either: Either.type): EitherObjectOps =
-    new EitherObjectOps(either) // scalastyle:off ensure.single.space.after.token
+    new EitherObjectOps(either)
 
   implicit final def catsSyntaxLeft[A, B](left: Left[A, B]): LeftOps[A, B] = new LeftOps(left)
 
@@ -334,7 +334,7 @@ final class EitherOps[A, B](private val eab: Either[A, B]) extends AnyVal {
   def liftTo[F[_]](implicit F: ApplicativeError[F, _ >: A]): F[B] = F.fromEither(eab)
 }
 
-final class EitherObjectOps(private val either: Either.type) extends AnyVal { // scalastyle:off ensure.single.space.after.token
+final class EitherObjectOps(private val either: Either.type) extends AnyVal {
   def left[A, B](a: A): Either[A, B] = Left(a)
 
   def right[A, B](b: B): Either[A, B] = Right(b)

free/src/main/scala/cats/free/FreeApplicative.scala

@@ -44,7 +44,6 @@ sealed abstract class FreeApplicative[F[_], A] extends Product with Serializable
    * Interprets/Runs the sequence of operations using the semantics of `Applicative` G[_].
    * Tail recursive.
    */
-  // scalastyle:off method.length
   final def foldMap[G[_]](f: F ~> G)(implicit G: Applicative[G]): G[A] = {
     import FreeApplicative._
     // the remaining arguments to G[A => B]'s
@@ -127,7 +126,6 @@ sealed abstract class FreeApplicative[F[_], A] extends Product with Serializable
 
     loop().asInstanceOf[G[A]]
   }
-  // scalastyle:on method.length
 
   /**
    * Interpret/run the operations using the semantics of `Applicative[F]`.

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

@@ -30,7 +30,7 @@ object SerializableLaws {
 
         val baos = new ByteArrayOutputStream()
         val oos = new ObjectOutputStream(baos)
-        var ois: ObjectInputStream = null // scalastyle:ignore null
+        var ois: ObjectInputStream = null
         try {
           oos.writeObject(a)
           oos.close()
@@ -44,7 +44,7 @@ object SerializableLaws {
             Result(status = Exception(t))
         } finally {
           oos.close()
-          if (ois != null) ois.close() // scalastyle:ignore null
+          if (ois != null) ois.close()
         }
       }
     } else Prop(_ => Result(status = Proof))

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

@@ -65,13 +65,9 @@ private[kernel] class HashCompat {
 
     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)
@@ -90,9 +86,7 @@ private[kernel] class HashCompat {
           h = mix(h, A.hash(it.next()))
           i += 1
         }
-        // scalastyle:off
         return finalizeHash(h, i)
-        // scalastyle:on
       }
       prev = hash
       i += 1

kernel/src/main/scala-2.13+/cats/kernel/instances/arraySeq/package.scala

@@ -1,4 +1,4 @@
 package cats.kernel
 package instances
 
-package object arraySeq extends ArraySeqInstances // scalastyle:ignore package.object.name
+package object arraySeq extends ArraySeqInstances

kernel/src/main/scala/cats/kernel/Comparison.scala

@@ -18,7 +18,7 @@ object Comparison {
   def fromInt(int: Int): Comparison =
     if (int > 0) Comparison.GreaterThan
     else if (int == 0) Comparison.EqualTo
-    else Comparison.LessThan // scalastyle:ignore ensure.single.space.after.token
+    else Comparison.LessThan
 
   def fromDouble(double: Double): Option[Comparison] =
     if (double.isNaN) None

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

@@ -35,7 +35,6 @@ object StaticMethods extends cats.kernel.compat.HashCompat {
     override def iterator: Iterator[A] = m.iterator
   }
 
-  // scalastyle:off return
   def iteratorCompare[A](xs: Iterator[A], ys: Iterator[A])(implicit ev: Order[A]): Int = {
     while (true) {
       if (xs.hasNext) {
@@ -86,7 +85,6 @@ object StaticMethods extends cats.kernel.compat.HashCompat {
     }
     true
   }
-  // scalastyle:on return
 
   def combineNIterable[A, R](b: mutable.Builder[A, R], x: Iterable[A], n: Int): R = {
     var i = n

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

@@ -1,4 +1,4 @@
 package cats.kernel
 package instances
 
-package object bigDecimal extends BigDecimalInstances // scalastyle:ignore package.object.name
+package object bigDecimal extends BigDecimalInstances

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

@@ -1,4 +1,4 @@
 package cats.kernel
 package instances
 
-package object bigInt extends BigIntInstances // scalastyle:ignore package.object.name
+package object bigInt extends BigIntInstances

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

@@ -1,4 +1,4 @@
 package cats.kernel
 package instances
 
-package object bitSet extends BitSetInstances // scalastyle:ignore package.object.name
+package object bitSet extends BitSetInstances