From 88c5b410aa453268133c6a3559dddeee7f34037f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Bargull?= <andre.bargull@gmail.com>
Date: Mon, 12 May 2025 15:58:00 +0200
Subject: [PATCH] Add coverage for converting negative fractional index to zero
 in (Typed)Array.prototype.with

JSC doesn't handle this correctly for `TypedArray.prototype.with`.
---
 ...tive-fractional-index-truncated-to-zero.js | 26 ++++++++++++++++
 ...tive-fractional-index-truncated-to-zero.js | 30 +++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 test/built-ins/Array/prototype/with/negative-fractional-index-truncated-to-zero.js
 create mode 100644 test/built-ins/TypedArray/prototype/with/negative-fractional-index-truncated-to-zero.js

diff --git a/test/built-ins/Array/prototype/with/negative-fractional-index-truncated-to-zero.js b/test/built-ins/Array/prototype/with/negative-fractional-index-truncated-to-zero.js
new file mode 100644
index 0000000000..ab50faeb4f
--- /dev/null
+++ b/test/built-ins/Array/prototype/with/negative-fractional-index-truncated-to-zero.js
@@ -0,0 +1,26 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-array.prototype.with
+description: >
+  Negative fractional index which is truncated to zero.
+info: |
+  Array.prototype.with ( index, value )
+
+  ...
+  3. Let relativeIndex be ? ToIntegerOrInfinity(index).
+  ...
+
+  ToIntegerOrInfinity ( argument )
+
+  1. Let number be ? ToNumber(argument).
+  2. If number is one of NaN, +0𝔽, or -0𝔽, return 0.
+  3. If number is +∞𝔽, return +∞.
+  4. If number is -∞𝔽, return -∞.
+  5. Return truncate(ℝ(number)).
+features: [change-array-by-copy]
+---*/
+
+var result = [0].with(-0.5, 123);
+assert.sameValue(result[0], 123);
diff --git a/test/built-ins/TypedArray/prototype/with/negative-fractional-index-truncated-to-zero.js b/test/built-ins/TypedArray/prototype/with/negative-fractional-index-truncated-to-zero.js
new file mode 100644
index 0000000000..15428c5fa8
--- /dev/null
+++ b/test/built-ins/TypedArray/prototype/with/negative-fractional-index-truncated-to-zero.js
@@ -0,0 +1,30 @@
+// Copyright (C) 2025 André Bargull. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-%typedarray%.prototype.with
+description: >
+  Negative fractional index which is truncated to zero.
+info: |
+  %TypedArray%.prototype.with ( index, value )
+
+  ...
+  4. Let relativeIndex be ? ToIntegerOrInfinity(index).
+  ...
+
+  ToIntegerOrInfinity ( argument )
+
+  1. Let number be ? ToNumber(argument).
+  2. If number is one of NaN, +0𝔽, or -0𝔽, return 0.
+  3. If number is +∞𝔽, return +∞.
+  4. If number is -∞𝔽, return -∞.
+  5. Return truncate(ℝ(number)).
+features: [TypedArray, change-array-by-copy]
+includes: [testTypedArray.js]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var ta = new TA(1);
+  var result = ta.with(-0.5, 123);
+  assert.sameValue(result[0], 123);
+});