Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

34 files changed, 1006 insertions, 0 deletions

diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/browser.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/browser.js
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-clamped-between-zero-and-remaining-count.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-clamped-between-zero-and-remaining-count.js
new file mode 100644
index 0000000000..7cc84733e2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-clamped-between-zero-and-remaining-count.js
@@ -0,0 +1,39 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: deleteCount is clamped between zero and len - actualStart
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  10. Else,
+    a. Let dc be ? ToIntegerOrInfinity(deleteCount).
+    b. Let actualDeleteCount be the result of clamping dc between 0 and len - actualStart.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+assert.compareArray(
+  [0, 1, 2, 3, 4, 5].toSpliced(2, -1),
+  [0, 1, 2, 3, 4, 5]
+);
+
+assert.compareArray(
+  [0, 1, 2, 3, 4, 5].toSpliced(-4, -1),
+  [0, 1, 2, 3, 4, 5]
+);
+
+assert.compareArray(
+  [0, 1, 2, 3, 4, 5].toSpliced(2, 6),
+  [0, 1]
+);
+
+assert.compareArray(
+  [0, 1, 2, 3, 4, 5].toSpliced(-4, 6),
+  [0, 1]
+);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-missing.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-missing.js
new file mode 100644
index 0000000000..6e0903c21d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-missing.js
@@ -0,0 +1,22 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced deletes the elements after start when called with one argument
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  9. Else if deleteCount is not present, then
+    a. Let actualDeleteCount be len - actualStart.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = ["first", "second", "third"].toSpliced(1);
+
+assert.compareArray(result, ["first"]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-undefined.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-undefined.js
new file mode 100644
index 0000000000..ed1b4dffb7
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/deleteCount-undefined.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced(number, undefined) returns a copy of the original array
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  ...
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+  8. If start is not present, then
+    a. Let actualDeleteCount be 0.
+  9. Else if deleteCount is not present, then
+    a. Let actualDeleteCount be len - actualStart.
+  10. Else,
+    a. Let dc be ? ToIntegerOrInfinity(deleteCount).
+    b. Let actualDeleteCount be the result of clamping dc between 0 and len - actualStart.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = ["first", "second", "third"].toSpliced(1, undefined);
+
+assert.compareArray(result, ["first", "second", "third"]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/discarded-element-not-read.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/discarded-element-not-read.js
new file mode 100644
index 0000000000..1544086f47
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/discarded-element-not-read.js
@@ -0,0 +1,54 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced does not Get the discarded elements in the original array
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  ...
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+  8. If start is not present, then
+    a. Let actualDeleteCount be 0.
+  9. Else if deleteCount is not present, then
+    a. Let actualDeleteCount be len - actualStart.
+  10. Else,
+    a. Let dc be ? ToIntegerOrInfinity(deleteCount).
+    b. Let actualDeleteCount be the result of clamping dc between 0 and len - actualStart.
+  11. Let newLen be len + insertCount - actualDeleteCount.
+  ...
+  15. Let r be actualStart + actualDeleteCount.
+  ...
+  18. Repeat, while i < newLen,
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Let from be ! ToString(𝔽(r)).
+    c. Let fromValue be ? Get(O, from).
+    d. Perform ! CreateDataPropertyOrThrow(A, Pi, fromValue).
+    e. Set i to i + 1.
+    f. Set r to r + 1.
+
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arrayLike = {
+  0: "a",
+  1: "b",
+  get 2() { throw new Test262Error(); },
+  3: "c",
+  length: 4,
+};
+
+/*
+ * In this example, just before step 18, i == 2 and r == 3.
+ * So A[2] is set to arrayLike[3] and arrayLike[2] is never read
+ * (since i and r both increase monotonically).
+ */
+var result = Array.prototype.toSpliced.call(arrayLike, 2, 1);
+assert.compareArray(result, ["a", "b", "c"]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/elements-read-in-order.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/elements-read-in-order.js
new file mode 100644
index 0000000000..da1b7fc905
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/elements-read-in-order.js
@@ -0,0 +1,61 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced reads the items of the original array in order
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  14. Let i be 0.
+  15. Let r be actualStart + actualDeleteCount.
+  16. Repeat, while i < actualStart,
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Let iValue be ? Get(O, Pi).
+    c. Perform ! CreateDataPropertyOrThrow(A, Pi, iValue).
+    d. Set i to i + 1.
+  17. For each element E of items, do
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Perform ! CreateDataPropertyOrThrow(A, Pi, E).
+    c. Set i to i + 1.
+  18. Repeat, while i < newLen,
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Let from be ! ToString(𝔽(r)).
+    c. Let fromValue be ? Get(O, from).
+    d. Perform ! CreateDataPropertyOrThrow(A, Pi, fromValue).
+    e. Set i to i + 1.
+    f. Set r to r + 1.
+  ...
+
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var order = [];
+
+var arrayLike = {
+  get 0() { order.push(0); return "a" },
+  get 1() { order.push(1); return "b" },
+  2: "none",
+  get 3() { order.push(3); return "c" },
+  length: 4,
+};
+
+var result = Array.prototype.toSpliced.call(arrayLike, 2, 1);
+assert.compareArray(result, ["a", "b", "c"]);
+
+assert.compareArray(order, [0, 1, 3]);
+
+order = [];
+var arr = [0, 1, "none", 3];
+Object.defineProperty(arr, 0, { get: function() { order.push(0); return "a" } });
+Object.defineProperty(arr, 1, { get: function() { order.push(1); return "b" } });
+Object.defineProperty(arr, 3, { get: function() { order.push(3); return "c" } });
+
+result = Array.prototype.toSpliced.call(arr, 2, 1);
+assert.compareArray(result, ["a", "b", "c"]);
+
+assert.compareArray(order, [0, 1, 3]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/frozen-this-value.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/frozen-this-value.js
new file mode 100644
index 0000000000..3013dee9f1
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/frozen-this-value.js
@@ -0,0 +1,20 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced works on frozen objects
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = Object.freeze([2, 0, 1]);
+var result = arr.toSpliced();
+assert.compareArray(result, [2, 0, 1]);
+
+var arrayLike = Object.freeze({ length: 3, 0: 0, 1: 1, 2: 2 });
+
+assert.compareArray(Array.prototype.toSpliced.call(arrayLike, 1, 1, 4, 5), [0, 4, 5, 2]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/holes-not-preserved.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/holes-not-preserved.js
new file mode 100644
index 0000000000..3fb2e312a2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/holes-not-preserved.js
@@ -0,0 +1,43 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced does not preserve holes in the array
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  13. Let k be 0.
+  14. Repeat, while k < actualStart,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let kValue be ? Get(O, Pk).
+    c. Perform ? CreateDataPropertyOrThrow(A, Pk, kValue).
+    d. Set k to k + 1.
+  ...
+  16. Repeat, while k < newLen,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let from be ! ToString(𝔽(k + actualDeleteCount - insertCount)).
+    c. Let fromValue be ? Get(O, from).
+    d. Perform ? CreateDataPropertyOrThrow(A, Pk, fromValue).
+    e. Set k to k + 1.
+  ...
+includes: [compareArray.js]
+features: [change-array-by-copy]
+---*/
+
+var arr = [0, /* hole */, 2, /* hole */, 4];
+Array.prototype[3] = 3;
+
+var spliced = arr.toSpliced(0, 0);
+assert.compareArray(spliced, [0, undefined, 2, 3, 4]);
+assert(spliced.hasOwnProperty(1));
+assert(spliced.hasOwnProperty(3));
+
+spliced = arr.toSpliced(0, 0, -1);
+assert.compareArray(spliced, [-1, 0, undefined, 2, 3, 4]);
+assert(spliced.hasOwnProperty(1));
+assert(spliced.hasOwnProperty(3));
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/ignores-species.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/ignores-species.js
new file mode 100644
index 0000000000..fd55356656
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/ignores-species.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced ignores @@species
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  12. Let A be ? ArrayCreate(𝔽(newLen)).
+  ...
+features: [change-array-by-copy]
+---*/
+
+var a = [];
+a.constructor = {};
+a.constructor[Symbol.species] = function () {}
+
+assert.sameValue(Object.getPrototypeOf(a.toSpliced(0, 0)), Array.prototype);
+
+var b = [];
+Object.defineProperty(b, "constructor", {
+  get() {
+    throw new Test262Error("Should not get .constructor");
+  }
+});
+
+b.toSpliced(0, 0);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/immutable.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/immutable.js
new file mode 100644
index 0000000000..710da9916c
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/immutable.js
@@ -0,0 +1,19 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced does not mutate its this value
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [2, 0, 1];
+arr.toSpliced(0, 0, -1);
+
+assert.compareArray(arr, [2, 0, 1]);
+assert.notSameValue(arr.toSpliced(0, 0, -1), arr);
+assert.notSameValue(arr.toSpliced(0, 1, -1), arr);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-casted-to-zero.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-casted-to-zero.js
new file mode 100644
index 0000000000..de36d2c41a
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-casted-to-zero.js
@@ -0,0 +1,23 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced treats its `this` value's `length` property as zero if the
+  property's value is not a positive integer.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+assert.compareArray(Array.prototype.toSpliced.call({ length: -2 }, 0, 0, 2, 3), [2, 3]);
+assert.compareArray(Array.prototype.toSpliced.call({ length: "dog" }, 0, 0, 2, 3), [2, 3]);
+assert.compareArray(Array.prototype.toSpliced.call({ length: NaN }, 0, 0, 2, 3), [2, 3]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-clamped-to-2pow53minus1.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-clamped-to-2pow53minus1.js
new file mode 100644
index 0000000000..0ce88ef200
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-clamped-to-2pow53minus1.js
@@ -0,0 +1,36 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Length is clamped to 2^53-1 when they exceed the integer limit.
+info: |
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  ...
+
+  ToLength ( argument )
+
+  1. Let len be ? ToIntegerOrInfinity(argument).
+  2. If len ≤ 0, return +0𝔽.
+  3. Return 𝔽(min(len, 2^53 - 1))
+features: [change-array-by-copy, exponentiation]
+includes: [compareArray.js]
+---*/
+
+var arrayLike = {
+  "9007199254740989": 2 ** 53 - 3,
+  "9007199254740990": 2 ** 53 - 2,
+  "9007199254740991": 2 ** 53 - 1,
+  "9007199254740992": 2 ** 53,
+  "9007199254740994": 2 ** 53 + 2, // NOTE: 2 ** 53 + 1 is 2 ** 53
+  length: 2 ** 53 + 20,
+};
+
+var result = Array.prototype.toSpliced.call(arrayLike, 0, 2 ** 53 - 3);
+
+assert.sameValue(result.length, 2);
+assert.compareArray(result, [2 ** 53 - 3, 2 ** 53 - 2]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-decreased-while-iterating.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-decreased-while-iterating.js
new file mode 100644
index 0000000000..35d4767b8f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-decreased-while-iterating.js
@@ -0,0 +1,46 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced caches the length getting the array elements.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  ...
+  11. Let newLen be len + insertCount - actualDeleteCount.
+  ...
+  13. Let k be 0.
+  14. Repeat, while k < actualStart,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let kValue be ? Get(O, Pk).
+    c. Perform ? CreateDataPropertyOrThrow(A, Pk, kValue).
+    d. Set k to k + 1.
+  ...
+  16. Repeat, while k < newLen,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let from be ! ToString(𝔽(k + actualDeleteCount - insertCount)).
+    c. Let fromValue be ? Get(O, from).
+    d. Perform ? CreateDataPropertyOrThrow(A, Pk, fromValue).
+    e. Set k to k + 1.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [0, 1, 2, 3, 4, 5];
+Array.prototype[3] = 6;
+
+Object.defineProperty(arr, "2", {
+  get() {
+    arr.length = 1;
+    return 2;
+  }
+});
+
+assert.compareArray(arr.toSpliced(0, 0), [0, 1, 2, 6, undefined, undefined]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-exceeding-array-length-limit.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-exceeding-array-length-limit.js
new file mode 100644
index 0000000000..a8ad3e4624
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-exceeding-array-length-limit.js
@@ -0,0 +1,78 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced limits the length to 2 ** 32 - 1
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  3. Let len be ? LengthOfArrayLike(O).
+  ...
+  11. Let newLen be len + insertCount - actualDeleteCount.
+  12. If _newLen_ > 2 ** 53< - 1, throw a *TypeError* exception.
+  13. Let A be ? ArrayCreate(𝔽(newLen)).
+  ...
+
+  ArrayCreate ( length [, proto ] )
+
+  1. If length > 2 ** 32 - 1, throw a RangeError exception.
+features: [change-array-by-copy, exponentiation]
+---*/
+
+// Object with large "length" property
+var arrayLike = {
+  get "0"() {
+    throw new Test262Error("Get 0");
+  },
+  get "4294967295" () { // 2 ** 32 - 1
+    throw new Test262Error("Get 4294967295");
+  },
+  get "4294967296" () { // 2 ** 32
+    throw new Test262Error("Get 4294967296");
+  },
+  length: 2 ** 32
+};
+
+assert.throws(RangeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0);
+});
+
+arrayLike.length = 2 ** 32 - 1;
+assert.throws(RangeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 32;
+assert.throws(RangeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 32 + 1;
+assert.throws(RangeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 52 - 2;
+assert.throws(RangeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 53 - 1;
+assert.throws(TypeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 53;
+assert.throws(TypeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+arrayLike.length = 2 ** 53 + 1;
+assert.throws(TypeError, function() {
+  Array.prototype.toSpliced.call(arrayLike, 0, 0, 1);
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-increased-while-iterating.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-increased-while-iterating.js
new file mode 100644
index 0000000000..f125316834
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-increased-while-iterating.js
@@ -0,0 +1,39 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced caches the length getting the array elements.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  3. Let len be ? LengthOfArrayLike(O).
+  ...
+  5. Let k be 0.
+  6. Repeat, while k < len,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let kValue be ? Get(O, Pk).
+    ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [0, 1, 2];
+Object.defineProperty(arr, "0", {
+  get() {
+    arr.push(10);
+    return 0;
+  }
+});
+Object.defineProperty(arr, "2", {
+  get() {
+    arr.push(11);
+    return 2;
+  }
+});
+
+assert.compareArray(arr.toSpliced(1, 0, 0.5), [0, 0.5, 1, 2]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-tolength.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-tolength.js
new file mode 100644
index 0000000000..fc40bb8aa6
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/length-tolength.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced converts the this value length to a number.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+assert.compareArray(Array.prototype.toSpliced.call({ length: "2", 0: 0, 1: 1, 2: 2 }, 0, 0), [0, 1]);
+
+var arrayLike = {
+  length: {
+    valueOf: () => 2
+  },
+  0: 0,
+  1: 1,
+  2: 2,
+};
+
+assert.compareArray(Array.prototype.toSpliced.call(arrayLike, 0, 0), [0, 1]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/browser.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/browser.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/browser.js
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/length.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/length.js
new file mode 100644
index 0000000000..63916778a5
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/length.js
@@ -0,0 +1,32 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  The "length" property of Array.prototype.toSpliced
+info: |
+  17 ECMAScript Standard Built-in Objects
+
+  Every built-in function object, including constructors, has a length property
+  whose value is an integer. Unless otherwise specified, this value is equal to
+  the largest number of named arguments shown in the subclause headings for the
+  function description. Optional parameters (which are indicated with brackets:
+  [ ]) or rest parameters (which are shown using the form «...name») are not
+  included in the default argument count.
+
+  Unless otherwise specified, the length property of a built-in function object
+  has the attributes { [[Writable]]: false, [[Enumerable]]: false,
+    [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [change-array-by-copy]
+---*/
+
+verifyProperty(Array.prototype.toSpliced, "length", {
+  value: 2,
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/name.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/name.js
new file mode 100644
index 0000000000..9025e4e34f
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/name.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced.name is "toSpliced".
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  17 ECMAScript Standard Built-in Objects:
+    Every built-in Function object, including constructors, that is not
+    identified as an anonymous function has a name property whose value
+    is a String.
+
+    Unless otherwise specified, the name property of a built-in Function
+    object, if it exists, has the attributes { [[Writable]]: false,
+    [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [change-array-by-copy]
+---*/
+
+verifyProperty(Array.prototype.toSpliced, "name", {
+  value: "toSpliced",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/property-descriptor.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/property-descriptor.js
new file mode 100644
index 0000000000..9c9eadef59
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/property-descriptor.js
@@ -0,0 +1,27 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  "toSpliced" property of Array.prototype
+info: |
+  17 ECMAScript Standard Built-in Objects
+
+  Every other data property described in clauses 18 through 26 and in Annex B.2
+  has the attributes { [[Writable]]: true, [[Enumerable]]: false,
+    [[Configurable]]: true } unless otherwise specified.
+includes: [propertyHelper.js]
+features: [change-array-by-copy]
+---*/
+
+assert.sameValue(typeof Array.prototype.toSpliced, "function", "typeof");
+
+verifyProperty(Array.prototype, "toSpliced", {
+  value: Array.prototype.toSpliced,
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/shell.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/metadata/shell.js
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/mutate-while-iterating.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/mutate-while-iterating.js
new file mode 100644
index 0000000000..208976b7cb
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/mutate-while-iterating.js
@@ -0,0 +1,52 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced gets array elements one at a time.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  16. Repeat, while i < actualStart,
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Let iValue be ? Get(O, Pi).
+    c. Perform ! CreateDataPropertyOrThrow(A, Pi, iValue).
+    d. Set i to i + 1.
+  ...
+  18. Repeat, while i < newLen,
+    a. Let Pi be ! ToString(𝔽(i)).
+    b. Let from be ! ToString(𝔽(r)).
+    c. Let fromValue be ? Get(O, from).
+    d. Perform ! CreateDataPropertyOrThrow(A, Pi, fromValue).
+    e. Set i to i + 1.
+    f. Set r to r + 1.
+  ...
+
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [0, 1, 2, 3];
+var zerothElementStorage = arr[0];
+Object.defineProperty(arr, "0", {
+  get() {
+    arr[1] = 42;
+    return zerothElementStorage;
+  },
+  set(v) {
+    zerothElementStorage = v;
+  }
+});
+Object.defineProperty(arr, "2", {
+  get() {
+    arr[0] = 17;
+    arr[3] = 37;
+    return 2;
+  }
+});
+
+assert.compareArray(arr.toSpliced(1, 0, 0.5), [0, 0.5, 42, 2, 37]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/not-a-constructor.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/not-a-constructor.js
new file mode 100644
index 0000000000..533e8c9eaa
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/not-a-constructor.js
@@ -0,0 +1,34 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  Array.prototype.toSpliced does not implement [[Construct]], is not new-able
+info: |
+  ECMAScript Function Objects
+
+  Built-in function objects that are not identified as constructors do not
+  implement the [[Construct]] internal method unless otherwise specified in
+  the description of a particular function.
+
+  sec-evaluatenew
+
+  ...
+  7. If IsConstructor(constructor) is false, throw a TypeError exception.
+  ...
+includes: [isConstructor.js]
+features: [change-array-by-copy, Reflect.construct]
+---*/
+
+assert.sameValue(
+  isConstructor(Array.prototype.toSpliced),
+  false,
+  'isConstructor(Array.prototype.toSpliced) must return false'
+);
+
+assert.throws(TypeError, () => {
+  new Array.prototype.toSpliced();
+}, '`new Array.prototype.toSpliced()` throws TypeError');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/shell.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/shell.js
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/shell.js
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-missing.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-missing.js
new file mode 100644
index 0000000000..19688d17af
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-missing.js
@@ -0,0 +1,29 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced returns a copy of the array if called with zero arguments
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  ...
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+  8. If start is not present, then
+    a. Let actualDeleteCount be 0.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+let arr = ["first", "second", "third"];
+let result = arr.toSpliced();
+
+assert.compareArray(result, arr);
+assert.notSameValue(result, arr);
+
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-undefineds.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-undefineds.js
new file mode 100644
index 0000000000..a07388dca2
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-and-deleteCount-undefineds.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced(undefined, undefined) returns a copy of the original array
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  ...
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+  8. If start is not present, then
+    a. Let actualDeleteCount be 0.
+  8. Else if deleteCount is not present, then
+    a. Let actualDeleteCount be len - actualStart.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+let arr = ["first", "second", "third"];
+let result = arr.toSpliced(undefined, undefined);
+
+assert.compareArray(result, arr);
+assert.notSameValue(result, arr);
+
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-bigger-than-length.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-bigger-than-length.js
new file mode 100644
index 0000000000..ca073db0e0
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-bigger-than-length.js
@@ -0,0 +1,25 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced clamps the start argument to the this value length.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  4. If relativeStart is -∞, let actualStart be 0.
+  5. Else if relativeStart < 0, let actualStart be max(len + relativeStart, 0).
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = [0, 1, 2, 3, 4].toSpliced(10, 1, 5, 6);
+assert.compareArray(result, [0, 1, 2, 3, 4, 5, 6]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-infinity-is-zero.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-infinity-is-zero.js
new file mode 100644
index 0000000000..cc025bd98e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-infinity-is-zero.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced treats negative Infinity as zero for start.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  4. If relativeStart is -∞, let actualStart be 0.
+  5. Else if relativeStart < 0, let actualStart be max(len + relativeStart, 0).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = [0, 1, 2, 3, 4].toSpliced(-Infinity, 2);
+assert.compareArray(result, [2, 3, 4]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-less-than-minus-length-is-zero.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-less-than-minus-length-is-zero.js
new file mode 100644
index 0000000000..79ccf7b51b
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-less-than-minus-length-is-zero.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced treats a value smaller than -length as zero for start.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  4. If relativeStart is -∞, let actualStart be 0.
+  5. Else if relativeStart < 0, let actualStart be max(len + relativeStart, 0).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = [0, 1, 2, 3, 4].toSpliced(-20, 2);
+assert.compareArray(result, [2, 3, 4]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-subtracted-from-length.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-subtracted-from-length.js
new file mode 100644
index 0000000000..4bbd45e665
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-neg-subtracted-from-length.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced treats a negative start as relative to the end.
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  ...
+  2. Let len be ? LengthOfArrayLike(O).
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  4. If relativeStart is -∞, let actualStart be 0.
+  5. Else if relativeStart < 0, let actualStart be max(len + relativeStart, 0).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = [0, 1, 2, 3, 4].toSpliced(-3, 2);
+assert.compareArray(result, [0, 1, 4]);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-undefined-and-deleteCount-missing.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-undefined-and-deleteCount-missing.js
new file mode 100644
index 0000000000..1cc6c57ad9
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/start-undefined-and-deleteCount-missing.js
@@ -0,0 +1,28 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: Array.prototype.toSpliced(undefined) returns an empty array
+info: |
+  22.1.3.25 Array.prototype.toSpliced (start, deleteCount , ...items )
+
+  ...
+  3. Let relativeStart be ? ToIntegerOrInfinity(start).
+  ...
+  6. Else, let actualStart be min(relativeStart, len).
+  ...
+  8. If start is not present, then
+    a. Let actualDeleteCount be 0.
+  8. Else if deleteCount is not present, then
+    a. Let actualDeleteCount be len - actualStart.
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var result = ["first", "second", "third"].toSpliced(undefined);
+
+assert.compareArray(result, []);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-boolean.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-boolean.js
new file mode 100644
index 0000000000..0f97abcd1d
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-boolean.js
@@ -0,0 +1,31 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced converts booleans to objects
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  1. Let O be ? ToObject(this value).
+  2. Let len be ? LengthOfArrayLike(O).
+  ...
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+assert.compareArray(Array.prototype.toSpliced.call(true, 0, 0), []);
+assert.compareArray(Array.prototype.toSpliced.call(false, 0, 0), []);
+
+/* Add length and indexed properties to `Boolean.prototype` */
+Boolean.prototype.length = 3;
+assert.compareArray(Array.prototype.toSpliced.call(true, 0, 0), [undefined, undefined, undefined]);
+assert.compareArray(Array.prototype.toSpliced.call(false, 0, 0), [undefined, undefined, undefined]);
+delete Boolean.prototype.length;
+Boolean.prototype[0] = "monkeys";
+Boolean.prototype[2] = "bogus";
+assert.compareArray(Array.prototype.toSpliced.call(true, 0, 0), []);
+assert.compareArray(Array.prototype.toSpliced.call(false, 0, 0), []);
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-nullish.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-nullish.js
new file mode 100644
index 0000000000..1230d05f00
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/this-value-nullish.js
@@ -0,0 +1,24 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced throws if the receiver is null or undefined
+info: |
+  Array.prototype.toSpliced ( start, deleteCount, ...items )
+
+  1. Let O be ? ToObject(this value).
+  ...
+features: [change-array-by-copy]
+---*/
+
+assert.throws(TypeError, () => {
+  Array.prototype.toSpliced.call(null, 0, 0);
+}, '`Array.prototype.toSpliced.call(null)` throws TypeError');
+
+assert.throws(TypeError, () => {
+  Array.prototype.toSpliced.call(undefined, 0, 0);
+}, '`Array.prototype.toSpliced.call(undefined)` throws TypeError');
+
+reportCompare(0, 0);
diff --git a/js/src/tests/test262/built-ins/Array/prototype/toSpliced/unmodified.js b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/unmodified.js
new file mode 100644
index 0000000000..d2983fd830
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/toSpliced/unmodified.js
@@ -0,0 +1,17 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.toSpliced
+description: >
+  Array.prototype.toSpliced returns a new array even if it the result is equal to the original array
+features: [change-array-by-copy]
+includes: [compareArray.js]
+---*/
+
+var arr = [1, 2, 3];
+var spliced = arr.toSpliced(1, 0);
+assert.notSameValue(arr, spliced);
+assert.compareArray(arr, spliced);
+
+reportCompare(0, 0);