From 7d074d28e3f7fa30d86e054945a453dcf99bb3df Mon Sep 17 00:00:00 2001
From: Alex <alex.simkin@outlook.com>
Date: Fri, 17 Jan 2025 21:36:57 +1100
Subject: [PATCH] identity both for vector. (#1454)

---
 .../test/scala/zio/prelude/IdentityBothSpec.scala  |  3 ++-
 .../main/scala/zio/prelude/AssociativeBoth.scala   |  7 ++++---
 .../abstraction-diagrams.md                        | 14 +++++++++++---
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/core-tests/shared/src/test/scala/zio/prelude/IdentityBothSpec.scala b/core-tests/shared/src/test/scala/zio/prelude/IdentityBothSpec.scala
index 28d121632..46e2fb880 100644
--- a/core-tests/shared/src/test/scala/zio/prelude/IdentityBothSpec.scala
+++ b/core-tests/shared/src/test/scala/zio/prelude/IdentityBothSpec.scala
@@ -14,7 +14,8 @@ object IdentityBothSpec extends ZIOBaseSpec {
         test("list")(checkAllLaws(IdentityBothLaws)(GenF.list, Gen.int)),
         test("option")(checkAllLaws(IdentityBothLaws)(GenF.option, Gen.int)),
         test("optional")(checkAllLaws(IdentityBothLaws)(optionalGenF, Gen.int)),
-        test("try")(checkAllLaws(IdentityBothLaws)(GenFs.tryScala, Gen.int))
+        test("try")(checkAllLaws(IdentityBothLaws)(GenFs.tryScala, Gen.int)),
+        test("vector")(checkAllLaws(IdentityBothLaws)(GenF.vector, Gen.int))
       )
     )
 }
diff --git a/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala b/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala
index f52959525..e643d2a57 100644
--- a/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala
+++ b/core/shared/src/main/scala/zio/prelude/AssociativeBoth.scala
@@ -1389,10 +1389,11 @@ object AssociativeBoth extends AssociativeBothLowPriority {
     }
 
   /**
-   * The `AssociativeBoth` instance for `Vector`.
+   * The `IdentityBoth` (and `AssociativeBoth`) instance for `Vector`.
    */
-  implicit val VectorAssociativeBoth: AssociativeBoth[Vector] =
-    new AssociativeBoth[Vector] {
+  implicit val VectorIdentityBoth: IdentityBoth[Vector] =
+    new IdentityBoth[Vector] {
+      def any: Vector[Any]                                               = Vector(())
       def both[A, B](fa: => Vector[A], fb: => Vector[B]): Vector[(A, B)] = fa.flatMap(a => fb.map(b => (a, b)))
     }
 
diff --git a/docs/functional-abstractions/abstraction-diagrams.md b/docs/functional-abstractions/abstraction-diagrams.md
index c38a9f719..722c2983d 100644
--- a/docs/functional-abstractions/abstraction-diagrams.md
+++ b/docs/functional-abstractions/abstraction-diagrams.md
@@ -155,8 +155,11 @@ classDiagram
   AssociativeBoth~F<_>~ <|-- CommutativeBoth~F<_>~
   AssociativeBoth~F<_>~ <|-- IdentityBoth~F<_>~
   class AssociativeBoth~F<_>~{
+    Exit[E, +*]
     Fiber[E, +*]
-    STM[R, E, +*]
+    NonEmptyChunk[+*]
+    ZSink[R, E, I, L, +*]
+    ZStream[R, E, +*]
 
     () both[A,B](=> F[A], => F[B]): F[(A,B)]
   }
@@ -175,18 +178,23 @@ classDiagram
     ZLayer[R, E, +*]
     ZManaged[R, E, +*]
     Failure[ZManaged[R, E, +*]]
-    ZSink[R, E, I, I, +*]
+    ZSink[R, E, I, L, +*]
     ZStream[R, E, +*]
   }
   class IdentityBoth~F<_>~{
+    Chunk[+*]
+    Config[+*]
     Either[L, +*]
     Failure[Either[+*, R]]
     Option[+*]
+    Optional[+*]
     Future[+*]
     Id[+*]
     List[+*]
+    STM[R, E, +*]
     Try[+*]
- 
+    Vector[+*]
+
     () any: F[Any]
   }
 ```