Deprecate @higherkind & @extension for Validated and offer concrete implementations (#267)

* Remove @higherkind generation, and deprecate generated code

* Remove @extensions for Validated Eq

* Deprecate @extension and add missing concrete implementations

* Add show on Companion of Validated

* Add order on Companion of Validated

* Remove dummy params from product

* Add deprecation to last methods

* Rewrite Validated branch

* Fix concrete bifoldable signatures

* ktlintFormat & fix docs

* Revert refactor from suspend Validated.catch to inline Validated.catch

* ktlintFormat

* Revert refactor from suspend Validated.catch to inline Validated.catch

* Fix incorrect import

* Add missing , in Validated docs

* Validated.kt doc fromOption -> fromNullable

* Docs green locally

* Re-add `unit` and make `DeprecatedLevel.ERROR`

* Remove TupleN from mapN signature

* Revert "Re-add `unit` and make `DeprecatedLevel.ERROR`, not possible due to @extensions"

This reverts commit c540118a09cbbb5e7cbef9566b9465e8bccc8138.

* ktlintFormat

* Fix Validated.mapN docs

* Retrigger build

* Update type arguments names, and param names

* Replace suspend catch with inline catch while maintaining binary compat

Co-authored-by: Rachel M. Carmena <[email protected]>

Author: nomisRev

arrow-libs/core/arrow-core-data/src/main/kotlin/arrow/core/Either.kt

@@ -869,7 +869,6 @@ sealed class Either<out A, out B> : EitherOf<A, B> {
    * Left(12).map { "flower" }  // Result: Left(12)
    * ```
    */
-  @Suppress("UNCHECKED_CAST")
   inline fun <C> map(f: (B) -> C): Either<A, C> =
     flatMap { Right(f(it)) }
 
@@ -996,6 +995,12 @@ sealed class Either<out A, out B> : EitherOf<A, B> {
 
     fun <R> right(right: R): Either<Nothing, R> = Right(right)
 
+    val leftUnit: Either<Unit, Nothing> = left(Unit)
+
+    val unit: Either<Nothing, Unit> = right(Unit)
+
+    fun <L> unit(): Either<L, Unit> = unit
+
     fun <A> fromNullable(a: A?): Either<Unit, A> = a?.right() ?: Unit.left()
 
     tailrec fun <L, A, B> tailRecM(a: A, f: (A) -> Kind<EitherPartialOf<L>, Either<A, B>>): Either<L, B> {
@@ -1077,6 +1082,12 @@ sealed class Either<out A, out B> : EitherOf<A, B> {
         .fold({ t: Throwable -> throwable(t) }, { b: B -> b.right() })
         .fold({ t: Throwable -> unrecoverableState(t); throw t }, { b: B -> b })
   }
+
+  fun <C> mapConst(c: C): Either<A, C> =
+    map { c }
+
+  fun void(): Either<A, Unit> =
+    mapConst(Unit)
 }
 
 fun <L> Left(left: L): Either<L, Nothing> = Left(left)

arrow-libs/core/arrow-core-data/src/main/kotlin/arrow/core/ListK.kt

@@ -482,3 +482,9 @@ fun <A> List<A>.k(): ListK<A> = ListK(this)
 
 fun <A> listKOf(vararg elements: A): ListK<A> =
   listOf(*elements).k()
+
+fun <A, B> Iterable<A>.mapConst(b: B): List<B> =
+  map { b }
+
+fun <A> Iterable<A>.void(): List<Unit> =
+  mapConst(Unit)