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ljharb merged 1 commit into from
Apr 29, 2026
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Editorial: narrow some AO return types and parameter types #3826

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48 changes: 25 additions & 23 deletions spec.html
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Original file line number Diff line number Diff line change
Expand Up @@ -11310,7 +11310,7 @@ <h1>
CreateGlobalFunctionBinding (
_envRec_: a Global Environment Record,
_name_: a String,
_value_: an ECMAScript language value,
_value_: an ECMAScript function object,
_deletable_: a Boolean,
): either a normal completion containing ~unused~ or a throw completion
</h1>
Expand Down Expand Up @@ -11530,7 +11530,7 @@ <h1>
<emu-clause id="sec-newmoduleenvironment" type="abstract operation">
<h1>
NewModuleEnvironment (
_outerEnv_: an Environment Record,
_outerEnv_: a Global Environment Record,
): a Module Environment Record
</h1>
<dl class="header">
Expand Down Expand Up @@ -12308,7 +12308,7 @@ <h1>AgentCanSuspend ( ): a Boolean</h1>
</emu-clause>

<emu-clause id="sec-IncrementModuleAsyncEvaluationCount" type="abstract operation">
<h1>IncrementModuleAsyncEvaluationCount ( ): an integer</h1>
<h1>IncrementModuleAsyncEvaluationCount ( ): a non-negative integer</h1>
<dl class="header">
</dl>
<emu-alg>
Expand Down Expand Up @@ -14607,7 +14607,7 @@ <h1>
<emu-clause id="sec-createmappedargumentsobject" type="abstract operation">
<h1>
CreateMappedArgumentsObject (
_func_: an Object,
_func_: an ECMAScript function object,
_formals_: a Parse Node,
_argumentsList_: a List of ECMAScript language values,
_env_: an Environment Record,
Expand Down Expand Up @@ -19408,7 +19408,7 @@ <h1>
EvaluateNew (
_constructExpr_: a |NewExpression| Parse Node or a |MemberExpression| Parse Node,
_arguments_: ~empty~ or an |Arguments| Parse Node,
): either a normal completion containing an ECMAScript language value or an abrupt completion
): either a normal completion containing an Object or an abrupt completion
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -19532,7 +19532,7 @@ <h1>Runtime Semantics: Evaluation</h1>
</emu-clause>

<emu-clause id="sec-getsuperconstructor" type="abstract operation">
<h1>GetSuperConstructor ( ): an ECMAScript language value</h1>
<h1>GetSuperConstructor ( ): an Object or *null*</h1>
<dl class="header">
</dl>
<emu-alg>
Expand Down Expand Up @@ -20952,7 +20952,7 @@ <h1>
<h1>
EvaluateStringOrNumericBinaryExpression (
_leftOperand_: a Parse Node,
_opText_: a sequence of Unicode code points,
_opText_: `**`, `*`, `/`, `%`, `+`, `-`, `&lt;&lt;`, `&gt;&gt;`, `&gt;&gt;&gt;`, `&amp;`, `^`, or `|`,
_rightOperand_: a Parse Node,
): either a normal completion containing either a String, a BigInt, or a Number, or an abrupt completion
</h1>
Expand Down Expand Up @@ -33957,7 +33957,7 @@ <h1>
_year_: a Number,
_month_: a Number,
_date_: a Number,
): a Number
): a finite Number or *NaN*

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The type "a finite Number or *NaN*" used in MakeDay is unknown type which ESMeta cannot understand. This type will be treated as bottom (⊥) type initially but will be joined with argument types when the algorithm is called.
</h1>
<dl class="header">
<dt>description</dt>
Expand All @@ -33981,7 +33981,7 @@ <h1>
MakeDate (
_day_: a Number,
_time_: a Number,
): a Number
): a finite Number or *NaN*

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The type "a finite Number or *NaN*" used in MakeDate is unknown type which ESMeta cannot understand. This type will be treated as bottom (⊥) type initially but will be joined with argument types when the algorithm is called.
</h1>
<dl class="header">
<dt>description</dt>
Expand Down Expand Up @@ -34017,7 +34017,7 @@ <h1>
<h1>
TimeClip (
_time_: a Number,
): a Number
): a time value

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The type "a time value" used in TimeClip is unknown type which ESMeta cannot understand. This type will be treated as bottom (⊥) type initially but will be joined with argument types when the algorithm is called.
</h1>
<dl class="header">
<dt>description</dt>
Expand Down Expand Up @@ -39496,7 +39496,7 @@ <h1>
_str_: a String,
_index_: a non-negative integer,
_unicode_: a Boolean,
): an integer
): a non-negative integer
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -43544,7 +43544,7 @@ <h1>
_target_: an Object,
_iterable_: an ECMAScript language value, but not *undefined* or *null*,
_adder_: a function object,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
<dt>description</dt>
Expand Down Expand Up @@ -46580,7 +46580,7 @@ <h1>
ValidateAtomicAccess (
_taRecord_: a TypedArray With Buffer Witness Record,
_requestIndex_: an ECMAScript language value,
): either a normal completion containing an integer or a throw completion
): either a normal completion containing a non-negative integer or a throw completion
</h1>
<dl class="header">
</dl>
Expand All @@ -46601,7 +46601,7 @@ <h1>
ValidateAtomicAccessOnIntegerTypedArray (
_typedArray_: an ECMAScript language value,
_requestIndex_: an ECMAScript language value,
): either a normal completion containing an integer or a throw completion
): either a normal completion containing a non-negative integer or a throw completion
</h1>
<dl class="header">
</dl>
Expand All @@ -46615,7 +46615,7 @@ <h1>
<h1>
RevalidateAtomicAccess (
_typedArray_: a TypedArray,
_byteIndexInBuffer_: an integer,
_byteIndexInBuffer_: a non-negative integer,
): either a normal completion containing ~unused~ or a throw completion
</h1>
<dl class="header">
Expand Down Expand Up @@ -47716,7 +47716,9 @@ <h1>
1. If _value_ is a BigInt, throw a *TypeError* exception.
1. If _value_ is an Object and IsCallable(_value_) is *false*, then
1. Let _isArray_ be ? IsArray(_value_).
1. If _isArray_ is *true*, return ? SerializeJSONArray(_state_, _value_).
1. If _isArray_ is *true*, then
1. Assert: _value_ is an Array. _value_ is not a Proxy.

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@Jack-Works Jack-Works May 1, 2026

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Add this assert on engine262 breaks the following test262 tests:

  • staging/sm/RegExp/match-trace.js
  • built-ins/JSON/stringify/value-array-proxy.js
  • built-ins/JSON/stringify/value-array-abrupt.js

Is this correct?

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@michaelficarra michaelficarra May 1, 2026

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No, we actually suspect this is incorrect and will be sending a PR to correct it soon.

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@michaelficarra michaelficarra May 1, 2026

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See #3842.

1. Return ? SerializeJSONArray(_state_, _value_).
1. Return ? SerializeJSONObject(_state_, _value_).
1. Return *undefined*.
</emu-alg>
Expand Down Expand Up @@ -47909,7 +47911,7 @@ <h1>
<h1>
SerializeJSONArray (
_state_: a JSON Serialization Record,
_value_: an ECMAScript language value,
_value_: an Array,
): either a normal completion containing a String or a throw completion
</h1>
<dl class="header">
Expand Down Expand Up @@ -49699,7 +49701,7 @@ <h1>
_constructor_: a constructor,
_resultCapability_: a PromiseCapability Record,
_promiseResolve_: a function object,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -49766,7 +49768,7 @@ <h1>
_constructor_: a constructor,
_resultCapability_: a PromiseCapability Record,
_promiseResolve_: a function object,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -49854,7 +49856,7 @@ <h1>
_constructor_: a constructor,
_resultCapability_: a PromiseCapability Record,
_promiseResolve_: a function object,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -49932,7 +49934,7 @@ <h1>
_constructor_: a constructor,
_resultCapability_: a PromiseCapability Record,
_promiseResolve_: a function object,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
</dl>
Expand Down Expand Up @@ -49978,7 +49980,7 @@ <h1>
PromiseResolve (
_constructor_: an Object,
_resolution_: an ECMAScript language value,
): either a normal completion containing an ECMAScript language value or a throw completion
): either a normal completion containing an Object or a throw completion
</h1>
<dl class="header">
<dt>description</dt>
Expand Down Expand Up @@ -50115,7 +50117,7 @@ <h1>
_onFulfilled_: an ECMAScript language value,
_onRejected_: an ECMAScript language value,
optional _resultCapability_: a PromiseCapability Record,
): an ECMAScript language value
): an Object or *undefined*
</h1>
<dl class="header">
<dt>description</dt>
Expand Down
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