1 files changed, 52 insertions, 0 deletions
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
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+++ 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);