From 321426a8f78bf775f9db6f880a4de5f032bea2dc Mon Sep 17 00:00:00 2001
From: Alexander Rundberg <alex@sect.tech>
Date: Thu, 18 Jan 2024 15:38:30 +0100
Subject: [PATCH 1/3] deprecate Iterable#unzip in favor of stdlib method

From what I can tell the other unzip methods have no equivalent in the
stdlib.

NonEmptyList is of course covered by the Iterable#unzip, but still has
a use-case because of returning a pair of NonEmptyLists rather than
a pair of regular Lists.
---
 .../src/commonMain/kotlin/arrow/core/Iterable.kt          | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
index 6e84455e566..1c22d2cda53 100644
--- a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
+++ b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
@@ -844,6 +844,10 @@ public fun <A> Iterable<A>.salign(
  * <!--- KNIT example-iterable-11.kt -->
  * <!--- TEST lines.isEmpty() -->
  */
+@Deprecated(
+  "Unzip is being deprecated in favor of the standard library version.\n$NicheAPI",
+  ReplaceWith("unzip()", "kotlin.collections.unzip")
+)
 public fun <A, B> Iterable<Pair<A, B>>.unzip(): Pair<List<A>, List<B>> =
   fold(emptyList<A>() to emptyList()) { (l, r), x ->
     l + x.first to r + x.second
@@ -867,6 +871,10 @@ public fun <A, B> Iterable<Pair<A, B>>.unzip(): Pair<List<A>, List<B>> =
  * <!--- KNIT example-iterable-12.kt -->
  * <!--- TEST lines.isEmpty() -->
  */
+@Deprecated(
+  "Unzip is being deprecated in favor of the standard library version.\n$NicheAPI",
+  ReplaceWith("map(fc).unzip()", "kotlin.collections.unzip")
+)
 public inline fun <A, B, C> Iterable<C>.unzip(fc: (C) -> Pair<A, B>): Pair<List<A>, List<B>> =
   map(fc).unzip()
 

From e81b318c3045b859f1cd8f5498506c0191df0f15 Mon Sep 17 00:00:00 2001
From: Alexander Rundberg <alex@sect.tech>
Date: Thu, 18 Jan 2024 16:53:18 +0100
Subject: [PATCH 2/3] delegate Iterator#unzip to standard library unzip

---
 .../src/commonMain/kotlin/arrow/core/Iterable.kt           | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
index 1c22d2cda53..2b5e8d16ea7 100644
--- a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
+++ b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/Iterable.kt
@@ -21,6 +21,7 @@ import arrow.typeclasses.SemigroupDeprecation
 import arrow.typeclasses.combine
 import kotlin.experimental.ExperimentalTypeInference
 import kotlin.jvm.JvmName
+import kotlin.collections.unzip as stdlibUnzip
 
 public inline fun <B, C, D, E> Iterable<B>.zip(
   c: Iterable<C>,
@@ -849,9 +850,7 @@ public fun <A> Iterable<A>.salign(
   ReplaceWith("unzip()", "kotlin.collections.unzip")
 )
 public fun <A, B> Iterable<Pair<A, B>>.unzip(): Pair<List<A>, List<B>> =
-  fold(emptyList<A>() to emptyList()) { (l, r), x ->
-    l + x.first to r + x.second
-  }
+   stdlibUnzip()
 
 /**
  * after applying the given function unzip the resulting structure into its elements.
@@ -876,7 +875,7 @@ public fun <A, B> Iterable<Pair<A, B>>.unzip(): Pair<List<A>, List<B>> =
   ReplaceWith("map(fc).unzip()", "kotlin.collections.unzip")
 )
 public inline fun <A, B, C> Iterable<C>.unzip(fc: (C) -> Pair<A, B>): Pair<List<A>, List<B>> =
-  map(fc).unzip()
+  map(fc).stdlibUnzip()
 
 /**
  * splits a union into its component parts.

From 484e3df81fe76a22095e171577e11a0a6917d53c Mon Sep 17 00:00:00 2001
From: Alexander Rundberg <alex@sect.tech>
Date: Thu, 18 Jan 2024 17:16:12 +0100
Subject: [PATCH 3/3] change NonEmptyList#unzip to use stdlib method

---
 .../src/commonMain/kotlin/arrow/core/NonEmptyList.kt      | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/NonEmptyList.kt b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/NonEmptyList.kt
index 880202ba5d7..8ea4104e146 100644
--- a/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/NonEmptyList.kt
+++ b/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/NonEmptyList.kt
@@ -10,6 +10,7 @@ import arrow.typeclasses.SemigroupDeprecation
 import arrow.typeclasses.combine
 import kotlin.experimental.ExperimentalTypeInference
 import kotlin.jvm.JvmStatic
+import kotlin.collections.unzip as stdlibUnzip
 
 public typealias Nel<A> = NonEmptyList<A>
 
@@ -424,11 +425,8 @@ public fun <A, B> NonEmptyList<Pair<A, B>>.unzip(): Pair<NonEmptyList<A>, NonEmp
   this.unzip(::identity)
 
 public fun <A, B, C> NonEmptyList<C>.unzip(f: (C) -> Pair<A, B>): Pair<NonEmptyList<A>, NonEmptyList<B>> =
-  this.map(f).let { nel ->
-    nel.tail.unzip().let {
-      NonEmptyList(nel.head.first, it.first) to
-        NonEmptyList(nel.head.second, it.second)
-    }
+  map(f).stdlibUnzip().let { (l1, l2) ->
+    l1.toNonEmptyListOrNull()!! to l2.toNonEmptyListOrNull()!!
   }
 
 @Deprecated(