1 files changed, 39 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/predicate-may-detach-buffer.js b/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/predicate-may-detach-buffer.js
new file mode 100644
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+++ b/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/predicate-may-detach-buffer.js
@@ -0,0 +1,39 @@
+// Copyright (C) 2021 Microsoft. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.findlastindex
+description: >
+  Predicate may detach the buffer
+info: |
+  %TypedArray%.prototype.findLastIndex ( predicate [ , thisArg ] )
+
+  ...
+  6. Repeat, while k ≥ 0,
+    a. Let Pk be ! ToString(𝔽(k)).
+    b. Let kValue be ! Get(O, Pk).
+    c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
+  ...
+
+  IntegerIndexedElementGet ( O, index )
+
+    Let buffer be the value of O's [[ViewedArrayBuffer]] internal slot.
+    If IsDetachedBuffer(buffer) is true, return undefined.
+
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [TypedArray, array-find-from-last]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var sample = new TA(2);
+  var loops = 0;
+
+  sample.findLastIndex(function() {
+    if (loops === 0) {
+      $DETACHBUFFER(sample.buffer);
+    }
+    loops++;
+  });
+  assert.sameValue(loops, 2, "predicate is called once");
+});
+
+reportCompare(0, 0);