Specialised Option.tapEach to preserve the type

Author: gdiet

src/main/scala/scala/collection/next/package.scala

@@ -19,4 +19,15 @@ package object next {
     col: IterableOnceOps[A, CC, C]
   ): NextIterableOnceOpsExtensions[A, CC, C] =
     new NextIterableOnceOpsExtensions(col)
+
+  implicit final class OptionOpsExtensions[A](val v: Option[A]) extends AnyVal {
+    /** Apply the side-effecting function $f to the option's value,
+      * if it is nonempty. Otherwise, do nothing.
+      *
+      * @param f a function to apply to the option's value
+      * @tparam B the return type of f
+      * @return the option
+      */
+    def tapEach[B](f: A => B): Option[A] = { v.foreach(f); v }
+  }
 }

src/test/scala/scala/collection/next/TestOptionOpsExtensions.scala

@@ -0,0 +1,21 @@
+/*
+ * Scala (https://www.scala-lang.org)
+ *
+ * Copyright EPFL and Lightbend, Inc.
+ *
+ * Licensed under Apache License 2.0
+ * (http://www.apache.org/licenses/LICENSE-2.0).
+ *
+ * See the NOTICE file distributed with this work for
+ * additional information regarding copyright ownership.
+ */
+
+package scala.collection.next
+
+import org.junit.Assert._
+import org.junit.Test
+
+final class TestOptionOpsExtensions {
+  // Compile checks the return type, no need to run as test.
+  def tapEachReturnType(): Option[Int] = Option(5).tapEach(identity)
+}