Normative: IntegerIndexedElementSet should always indicate success (#…

…2210)

Resolves #2208.

spec.html

@@ -9180,9 +9180,7 @@ <h1>[[DefineOwnProperty]] ( _P_, _Desc_ )</h1>
               1. If _Desc_ has a [[Configurable]] field and if _Desc_.[[Configurable]] is *false*, return *false*.
               1. If _Desc_ has an [[Enumerable]] field and if _Desc_.[[Enumerable]] is *false*, return *false*.
               1. If _Desc_ has a [[Writable]] field and if _Desc_.[[Writable]] is *false*, return *false*.
-              1. If _Desc_ has a [[Value]] field, then
-                1. Let _value_ be _Desc_.[[Value]].
-                1. Return ? IntegerIndexedElementSet(_O_, _numericIndex_, _value_).
+              1. If _Desc_ has a [[Value]] field, perform ? IntegerIndexedElementSet(_O_, _numericIndex_, _Desc_.[[Value]]).
               1. Return *true*.
           1. Return ! OrdinaryDefineOwnProperty(_O_, _P_, _Desc_).
         </emu-alg>
@@ -9209,7 +9207,8 @@ <h1>[[Set]] ( _P_, _V_, _Receiver_ )</h1>
           1. If Type(_P_) is String, then
             1. Let _numericIndex_ be ! CanonicalNumericIndexString(_P_).
             1. If _numericIndex_ is not *undefined*, then
-              1. Return ? IntegerIndexedElementSet(_O_, _numericIndex_, _V_).
+              1. Perform ? IntegerIndexedElementSet(_O_, _numericIndex_, _V_).
+              1. Return *true*.
           1. Return ? OrdinarySet(_O_, _P_, _V_, _Receiver_).
         </emu-alg>
       </emu-clause>
@@ -9298,15 +9297,18 @@ <h1>IntegerIndexedElementSet ( _O_, _index_, _value_ )</h1>
           1. Assert: _O_ is an Integer-Indexed exotic object.
           1. If _O_.[[ContentType]] is ~BigInt~, let _numValue_ be ? ToBigInt(_value_).
           1. Otherwise, let _numValue_ be ? ToNumber(_value_).
-          1. If ! IsValidIntegerIndex(_O_, _index_) is *false*, return *false*.
-          1. Let _offset_ be _O_.[[ByteOffset]].
-          1. Let _arrayTypeName_ be the String value of _O_.[[TypedArrayName]].
-          1. Let _elementSize_ be the Element Size value specified in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _arrayTypeName_.
-          1. Let _indexedPosition_ be (ℝ(_index_) &times; _elementSize_) + _offset_.
-          1. Let _elementType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _arrayTypeName_.
-          1. Perform SetValueInBuffer(_O_.[[ViewedArrayBuffer]], _indexedPosition_, _elementType_, _numValue_, *true*, ~Unordered~).
-          1. Return *true*.
+          1. If ! IsValidIntegerIndex(_O_, _index_) is *true*, then
+            1. Let _offset_ be _O_.[[ByteOffset]].
+            1. Let _arrayTypeName_ be the String value of _O_.[[TypedArrayName]].
+            1. Let _elementSize_ be the Element Size value specified in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _arrayTypeName_.
+            1. Let _indexedPosition_ be (ℝ(_index_) &times; _elementSize_) + _offset_.
+            1. Let _elementType_ be the Element Type value in <emu-xref href="#table-the-typedarray-constructors"></emu-xref> for _arrayTypeName_.
+            1. Perform SetValueInBuffer(_O_.[[ViewedArrayBuffer]], _indexedPosition_, _elementType_, _numValue_, *true*, ~Unordered~).
+          1. Return NormalCompletion(*undefined*).
         </emu-alg>
+        <emu-note>
+          <p>This operation always appears to succeed, but it has no effect when attempting to write past the end of a TypedArray or to a TypedArray which is backed by a detached ArrayBuffer.</p>
+        </emu-note>
       </emu-clause>
     </emu-clause>