From 4e78f283e7a1b1b4d4e46fbcb85c331ebabc69ad Mon Sep 17 00:00:00 2001
From: "maksim.khramtsov" <maksim.khramtsov@btsdigital.kz>
Date: Tue, 20 Aug 2024 20:06:34 +0200
Subject: [PATCH 1/3] preserve `Array.replace` `Array.replaceOption`
 nonemptyness

---
 .changeset/rich-pumas-protect.md |  5 +++++
 packages/effect/src/Array.ts     | 26 ++++++++++++++++++++++----
 2 files changed, 27 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/rich-pumas-protect.md

diff --git a/.changeset/rich-pumas-protect.md b/.changeset/rich-pumas-protect.md
new file mode 100644
index 0000000000..46b622c0d0
--- /dev/null
+++ b/.changeset/rich-pumas-protect.md
@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+preserve `Array.replace` `Array.replaceOption` nonemptyness
diff --git a/packages/effect/src/Array.ts b/packages/effect/src/Array.ts
index 329220363e..9d6e5f71b4 100644
--- a/packages/effect/src/Array.ts
+++ b/packages/effect/src/Array.ts
@@ -1055,8 +1055,17 @@ export const insertAt: {
  * @since 2.0.0
  */
 export const replace: {
-  <B>(i: number, b: B): <A>(self: Iterable<A>) => Array<A | B>
-  <A, B>(self: Iterable<A>, i: number, b: B): Array<A | B>
+  <B>(
+    i: number,
+    b: B
+  ): <A, S extends Iterable<A> = Iterable<A>>(
+    self: S
+  ) => ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>
+  <A, B, S extends Iterable<A> = Iterable<A>>(
+    self: S,
+    i: number,
+    b: B
+  ): ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>
 } = dual(3, <A, B>(self: Iterable<A>, i: number, b: B): Array<A | B> => modify(self, i, () => b))
 
 /**
@@ -1072,8 +1081,17 @@ export const replace: {
  * @since 2.0.0
  */
 export const replaceOption: {
-  <B>(i: number, b: B): <A>(self: Iterable<A>) => Option<Array<A | B>>
-  <A, B>(self: Iterable<A>, i: number, b: B): Option<Array<A | B>>
+  <B>(
+    i: number,
+    b: B
+  ): <A, S extends Iterable<A> = Iterable<A>>(
+    self: Iterable<A>
+  ) => Option<ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>>
+  <A, B, S extends Iterable<A> = Iterable<A>>(
+    self: S,
+    i: number,
+    b: B
+  ): Option<ReadonlyArray.With<S, ReadonlyArray.Infer<S> | B>>
 } = dual(
   3,
   <A, B>(self: Iterable<A>, i: number, b: B): Option<Array<A | B>> => modifyOption(self, i, () => b)

From 4561cd1154533738f1079c31963311b505017dcf Mon Sep 17 00:00:00 2001
From: "maksim.khramtsov" <maksim.khramtsov@btsdigital.kz>
Date: Tue, 20 Aug 2024 21:03:24 +0200
Subject: [PATCH 2/3] fix typo

---
 .changeset/rich-pumas-protect.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.changeset/rich-pumas-protect.md b/.changeset/rich-pumas-protect.md
index 46b622c0d0..e8d499a826 100644
--- a/.changeset/rich-pumas-protect.md
+++ b/.changeset/rich-pumas-protect.md
@@ -2,4 +2,4 @@
 "effect": minor
 ---
 
-preserve `Array.replace` `Array.replaceOption` nonemptyness
+preserve `Array.replace` `Array.replaceOption` non emptiness

From d1c2f63d8c005ce36a0a524d6ffc0c65b3e023e9 Mon Sep 17 00:00:00 2001
From: "maksim.khramtsov" <maksim.khramtsov@btsdigital.kz>
Date: Wed, 21 Aug 2024 11:06:58 +0200
Subject: [PATCH 3/3] add dtslint tests

---
 packages/effect/dtslint/Array.ts | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/packages/effect/dtslint/Array.ts b/packages/effect/dtslint/Array.ts
index fc80439895..9c6ddb0888 100644
--- a/packages/effect/dtslint/Array.ts
+++ b/packages/effect/dtslint/Array.ts
@@ -1334,3 +1334,25 @@ Array.getSomes(hole<Iterable<Option.Option<number> | Option.Option<string>>>())
 
 // $ExpectType (string | number)[]
 Array.getSomes(hole<Iterable<Option.Option<number>> | Iterable<Option.Option<string>>>())
+
+// -------------------------------------------------------------------------------------
+// replace
+// -------------------------------------------------------------------------------------
+
+// $ExpectType string[]
+Array.replace([], 0, "a")
+
+// $ExpectType ("a" | 1 | 2)[]
+Array.replace(new Set([1, 2] as const), 0, "a" as const)
+
+// $ExpectType [number | "a", ...(number | "a")[]]
+Array.replace(Array.of(1), 0, "a" as const)
+
+// $ExpectType string[]
+pipe([], Array.replace(0, "a"))
+
+// $ExpectType ("a" | 1 | 2)[]
+pipe(new Set([1, 2] as const), Array.replace(0, "a" as const))
+
+// $ExpectType [number | "a", ...(number | "a")[]]
+pipe(Array.of(1), Array.replace(0, "a" as const))