From ab9d475159435d0a4fb11ccb8a069242aa50834b Mon Sep 17 00:00:00 2001
From: Mickemouse0 <31856324+Mickemouse0@users.noreply.github.com>
Date: Sun, 18 Jun 2023 00:55:13 +0200
Subject: [PATCH 1/5] Fixes to isArray

---
 src/entrypoints/is-array.d.ts |  2 +-
 src/tests/is-array.ts         | 96 ++++++++++++++++++++++++++++++++++-
 2 files changed, 96 insertions(+), 2 deletions(-)

diff --git a/src/entrypoints/is-array.d.ts b/src/entrypoints/is-array.d.ts
index 199bc66..583777e 100644
--- a/src/entrypoints/is-array.d.ts
+++ b/src/entrypoints/is-array.d.ts
@@ -1,3 +1,3 @@
 interface ArrayConstructor {
-  isArray(arg: any): arg is unknown[];
+  isArray<T>(arg: 0 extends 1 & T ? never : T): arg is 0 extends 1 & T ? never : T extends Array<unknown> | ReadonlyArray<unknown> ? T : T[] extends T ? T[] : never;
 }
diff --git a/src/tests/is-array.ts b/src/tests/is-array.ts
index daaa12c..2333c03 100644
--- a/src/tests/is-array.ts
+++ b/src/tests/is-array.ts
@@ -8,6 +8,30 @@ doNotExecute(() => {
   }
 });
 
+doNotExecute(() => {
+  const maybeArr = [1, 2, 3] as unknown[];
+
+  if (Array.isArray(maybeArr)) {
+    type tests = [Expect<Equal<typeof maybeArr, unknown[]>>];
+  }
+});
+
+doNotExecute(() => {
+  const maybeArr = [1, 2, 3] as any;
+
+  if (Array.isArray(maybeArr)) {
+    type tests = [Expect<Equal<typeof maybeArr, any[]>>];
+  }
+});
+
+doNotExecute(() => {
+  const maybeArr = [1, 2, 3] as any[];
+
+  if (Array.isArray(maybeArr)) {
+    type tests = [Expect<Equal<typeof maybeArr, any[]>>];
+  }
+});
+
 doNotExecute(() => {
   const arrOrString = [] as string[] | string;
 
@@ -17,9 +41,79 @@ doNotExecute(() => {
 });
 
 doNotExecute(() => {
-  let path: string | string[] = [];
+  const arrOrString = [] as readonly string[] | string;
+
+  if (Array.isArray(arrOrString)) {
+    type tests = [Expect<Equal<typeof arrOrString, readonly string[]>>];
+  }
+});
+
+doNotExecute(() => {
+  const arrOrString = [] as readonly string[] | string[] | string;
+
+  if (Array.isArray(arrOrString)) {
+    type tests = [Expect<Equal<typeof arrOrString, readonly string[] | string[]>>];
+  }
+});
+
+doNotExecute(() => {
+  const arrOrString = [] as string[] | string;
+
+  if (Array.isArray(arrOrString)) return;
+  type tests = [Expect<Equal<typeof arrOrString, string>>];
+});
+
+doNotExecute(() => {
+  const arrOrString = [] as readonly string[] | string;
+
+  if (Array.isArray(arrOrString)) return;
+  type tests = [Expect<Equal<typeof arrOrString, string>>];
+});
+
+doNotExecute(() => {
+  const arrOrString = [] as readonly string[] | string[] | string;
+
+  if (Array.isArray(arrOrString)) return;
+  type tests = [Expect<Equal<typeof arrOrString, string>>];
+});
+
+doNotExecute(() => {
+  let arrOrString = "" as string | [1, 2];
+
+  if (Array.isArray(arrOrString)) {
+    type tests = [Expect<Equal<typeof arrOrString, [1, 2]>>];
+  }
+});
+
+doNotExecute(() => {
+  let path = [] as string | string[];
 
   const paths = Array.isArray(path) ? path : [path];
 
   type tests = [Expect<Equal<typeof paths, string[]>>];
 });
+
+doNotExecute(() => {
+  function test<T>(value: T) {
+    type Unarray<T> = T extends Array<infer U> ? U : T;
+    const inner = <X extends Unarray<T>>(v: X[]) => {};
+
+    if (Array.isArray(value)) {
+      inner(value);
+    }
+  }
+});
+
+doNotExecute(async () => {
+  function makeArray<Item>(input: Item | ReadonlyArray<Item> | Array<Item>) {
+    if (Array.isArray(input)) {
+      return input;
+    }
+    return [input];
+  }
+
+  const [first] = makeArray([{ a: "1" }, { a: "2" }, { a: "3" }] as const);
+
+  // No error!
+  first.a;
+});

From d2918bb78b48874bfa27ec9b692c372f51b36945 Mon Sep 17 00:00:00 2001
From: Mickemouse0 <31856324+Mickemouse0@users.noreply.github.com>
Date: Sun, 18 Jun 2023 01:05:23 +0200
Subject: [PATCH 2/5] Update is-array.d.ts

---
 src/entrypoints/is-array.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/entrypoints/is-array.d.ts b/src/entrypoints/is-array.d.ts
index 583777e..8484b86 100644
--- a/src/entrypoints/is-array.d.ts
+++ b/src/entrypoints/is-array.d.ts
@@ -1,3 +1,3 @@
 interface ArrayConstructor {
-  isArray<T>(arg: 0 extends 1 & T ? never : T): arg is 0 extends 1 & T ? never : T extends Array<unknown> | ReadonlyArray<unknown> ? T : T[] extends T ? T[] : never;
+  isArray<T>(arg: 0 extends 1 & T ? never : T): arg is 0 extends 1 & T ? never : T extends unknown[] | readonly unknown[] ? T : T[] extends T ? T[] : never;
 }

From 710e603101b0b01ecae57c204f9aa5825b637955 Mon Sep 17 00:00:00 2001
From: Mickemouse0 <31856324+Mickemouse0@users.noreply.github.com>
Date: Tue, 20 Jun 2023 07:10:38 +0200
Subject: [PATCH 3/5] Improve readability

---
 src/entrypoints/is-array.d.ts | 2 +-
 src/entrypoints/utils.d.ts    | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/entrypoints/is-array.d.ts b/src/entrypoints/is-array.d.ts
index 8484b86..6b4b814 100644
--- a/src/entrypoints/is-array.d.ts
+++ b/src/entrypoints/is-array.d.ts
@@ -1,3 +1,3 @@
 interface ArrayConstructor {
-  isArray<T>(arg: 0 extends 1 & T ? never : T): arg is 0 extends 1 & T ? never : T extends unknown[] | readonly unknown[] ? T : T[] extends T ? T[] : never;
+  isArray<T>(arg: true extends TSReset.IsAny<T> ? never : T): arg is true extends TSReset.IsAny<T> ? never : T extends ReadonlyArray<unknown> ? T : Array<T> extends T ? Array<T> : never;
 }
diff --git a/src/entrypoints/utils.d.ts b/src/entrypoints/utils.d.ts
index 00171cb..4d7c6be 100644
--- a/src/entrypoints/utils.d.ts
+++ b/src/entrypoints/utils.d.ts
@@ -14,4 +14,7 @@ declare namespace TSReset {
     : T extends symbol
     ? symbol
     : T;
+
+    // https://stackoverflow.com/questions/49927523/disallow-call-with-any/49928360#49928360
+  type IsAny<T> = 0 extends 1 & T ? true : false;
 }

From db19046f4e69ed55a52e5ddb2a47070ae6b7d3c7 Mon Sep 17 00:00:00 2001
From: Mickemouse0 <31856324+Mickemouse0@users.noreply.github.com>
Date: Tue, 20 Jun 2023 07:12:37 +0200
Subject: [PATCH 4/5] Fix indentation

---
 src/entrypoints/utils.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/entrypoints/utils.d.ts b/src/entrypoints/utils.d.ts
index 4d7c6be..e1dc76c 100644
--- a/src/entrypoints/utils.d.ts
+++ b/src/entrypoints/utils.d.ts
@@ -15,6 +15,6 @@ declare namespace TSReset {
     ? symbol
     : T;
 
-    // https://stackoverflow.com/questions/49927523/disallow-call-with-any/49928360#49928360
+  // https://stackoverflow.com/questions/49927523/disallow-call-with-any/49928360#49928360
   type IsAny<T> = 0 extends 1 & T ? true : false;
 }

From 4be3b4f78716d649bc287a81f4ce8d92429abc46 Mon Sep 17 00:00:00 2001
From: Mickemouse0 <31856324+Mickemouse0@users.noreply.github.com>
Date: Fri, 23 Jun 2023 11:42:47 +0200
Subject: [PATCH 5/5] Remove invalid test

---
 src/tests/is-array.ts | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/src/tests/is-array.ts b/src/tests/is-array.ts
index 2333c03..e8ec25c 100644
--- a/src/tests/is-array.ts
+++ b/src/tests/is-array.ts
@@ -103,17 +103,3 @@ doNotExecute(() => {
     }
   }
 });
-
-doNotExecute(async () => {
-  function makeArray<Item>(input: Item | ReadonlyArray<Item> | Array<Item>) {
-    if (Array.isArray(input)) {
-      return input;
-    }
-    return [input];
-  }
-
-  const [first] = makeArray([{ a: "1" }, { a: "2" }, { a: "3" }] as const);
-
-  // No error!
-  first.a;
-});