diff --git a/polyfill/lib/calendar.mjs b/polyfill/lib/calendar.mjs
index dec2998ca9..63f3467a24 100644
--- a/polyfill/lib/calendar.mjs
+++ b/polyfill/lib/calendar.mjs
@@ -41,20 +41,14 @@ const impl = {};
 
 export class Calendar {
   constructor(id) {
-    // Note: if the argument is not passed, IsBuiltinCalendar("undefined") will fail. This check
-    //       exists only to improve the error message.
-    if (arguments.length < 1) {
-      throw new RangeError('missing argument: id is required');
-    }
-
-    id = ES.ToString(id);
-    if (!ES.IsBuiltinCalendar(id)) throw new RangeError(`invalid calendar identifier ${id}`);
+    const stringId = ES.RequireString(id);
+    if (!ES.IsBuiltinCalendar(stringId)) throw new RangeError(`invalid calendar identifier ${stringId}`);
     CreateSlots(this);
-    SetSlot(this, CALENDAR_ID, ES.ASCIILowercase(id));
+    SetSlot(this, CALENDAR_ID, ES.ASCIILowercase(stringId));
 
     if (typeof __debug__ !== 'undefined' && __debug__) {
       Object.defineProperty(this, '_repr_', {
-        value: `${this[Symbol.toStringTag]} <${id}>`,
+        value: `${this[Symbol.toStringTag]} <${stringId}>`,
         writable: false,
         enumerable: false,
         configurable: false
diff --git a/polyfill/lib/ecmascript.mjs b/polyfill/lib/ecmascript.mjs
index 25d54d96f2..404e5a111b 100644
--- a/polyfill/lib/ecmascript.mjs
+++ b/polyfill/lib/ecmascript.mjs
@@ -18,6 +18,7 @@ const ObjectCreate = Object.create;
 const ObjectDefineProperty = Object.defineProperty;
 const ObjectEntries = Object.entries;
 const ObjectGetOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
+const StringCtor = String;
 const StringFromCharCode = String.fromCharCode;
 const StringPrototypeCharCodeAt = String.prototype.charCodeAt;
 const StringPrototypeMatchAll = String.prototype.matchAll;
@@ -146,10 +147,27 @@ export function ToIntegerIfIntegral(value) {
   return number;
 }
 
+// This convenience function isn't in the spec, but is useful in the polyfill
+// for DRY and better error messages.
+export function RequireString(value) {
+  if (Type(value) !== 'String') {
+    // Use String() to ensure that Symbols won't throw
+    throw new TypeError(`expected a string, not ${StringCtor(value)}`);
+  }
+  return value;
+}
+
+// This function is an enum in the spec, but it's helpful to make it a
+// function in the polyfill.
+function ToPrimitiveAndRequireString(value) {
+  value = ToPrimitive(value, StringCtor);
+  return RequireString(value);
+}
+
 const BUILTIN_CASTS = new Map([
   ['year', ToIntegerWithTruncation],
   ['month', ToPositiveIntegerWithTruncation],
-  ['monthCode', ToString],
+  ['monthCode', ToPrimitiveAndRequireString],
   ['day', ToPositiveIntegerWithTruncation],
   ['hour', ToIntegerWithTruncation],
   ['minute', ToIntegerWithTruncation],
@@ -167,9 +185,9 @@ const BUILTIN_CASTS = new Map([
   ['milliseconds', ToIntegerIfIntegral],
   ['microseconds', ToIntegerIfIntegral],
   ['nanoseconds', ToIntegerIfIntegral],
-  ['era', ToString],
+  ['era', ToPrimitiveAndRequireString],
   ['eraYear', ToIntegerOrInfinity],
-  ['offset', ToString]
+  ['offset', ToPrimitiveAndRequireString]
 ]);
 
 const BUILTIN_DEFAULTS = new Map([
@@ -704,7 +722,7 @@ export function RegulateISOYearMonth(year, month, overflow) {
 
 export function ToTemporalDurationRecord(item) {
   if (Type(item) !== 'Object') {
-    return ParseTemporalDurationString(ToString(item));
+    return ParseTemporalDurationString(RequireString(item));
   }
   if (IsTemporalDuration(item)) {
     return {
@@ -986,7 +1004,7 @@ export function ToRelativeTemporalObject(options) {
   } else {
     let tzName, z;
     ({ year, month, day, hour, minute, second, millisecond, microsecond, nanosecond, calendar, tzName, offset, z } =
-      ParseISODateTime(ToString(relativeTo)));
+      ParseISODateTime(RequireString(relativeTo)));
     if (tzName) {
       timeZone = ToTemporalTimeZoneSlotValue(tzName);
       if (z) {
@@ -1134,7 +1152,7 @@ export function ToTemporalDate(item, options) {
     return CalendarDateFromFields(calendar, fields, options);
   }
   ToTemporalOverflow(options); // validate and ignore
-  let { year, month, day, calendar, z } = ParseTemporalDateString(ToString(item));
+  let { year, month, day, calendar, z } = ParseTemporalDateString(RequireString(item));
   if (z) throw new RangeError('Z designator not supported for PlainDate');
   if (!calendar) calendar = 'iso8601';
   if (!IsBuiltinCalendar(calendar)) throw new RangeError(`invalid calendar identifier ${calendar}`);
@@ -1208,7 +1226,7 @@ export function ToTemporalDateTime(item, options) {
     ToTemporalOverflow(options); // validate and ignore
     let z;
     ({ year, month, day, hour, minute, second, millisecond, microsecond, nanosecond, calendar, z } =
-      ParseTemporalDateTimeString(ToString(item)));
+      ParseTemporalDateTimeString(RequireString(item)));
     if (z) throw new RangeError('Z designator not supported for PlainDateTime');
     RejectDateTime(year, month, day, hour, minute, second, millisecond, microsecond, nanosecond);
     if (!calendar) calendar = 'iso8601';
@@ -1243,7 +1261,8 @@ export function ToTemporalInstant(item) {
     const TemporalInstant = GetIntrinsic('%Temporal.Instant%');
     return new TemporalInstant(GetSlot(item, EPOCHNANOSECONDS));
   }
-  const ns = ParseTemporalInstant(ToString(item));
+  item = ToPrimitive(item, StringCtor);
+  const ns = ParseTemporalInstant(RequireString(item));
   const TemporalInstant = GetIntrinsic('%Temporal.Instant%');
   return new TemporalInstant(ns);
 }
@@ -1273,7 +1292,7 @@ export function ToTemporalMonthDay(item, options) {
   }
 
   ToTemporalOverflow(options); // validate and ignore
-  let { month, day, referenceISOYear, calendar } = ParseTemporalMonthDayString(ToString(item));
+  let { month, day, referenceISOYear, calendar } = ParseTemporalMonthDayString(RequireString(item));
   if (calendar === undefined) calendar = 'iso8601';
   if (!IsBuiltinCalendar(calendar)) throw new RangeError(`invalid calendar identifier ${calendar}`);
   calendar = ASCIILowercase(calendar);
@@ -1315,7 +1334,7 @@ export function ToTemporalTime(item, overflow = 'constrain') {
       overflow
     ));
   } else {
-    ({ hour, minute, second, millisecond, microsecond, nanosecond } = ParseTemporalTimeString(ToString(item)));
+    ({ hour, minute, second, millisecond, microsecond, nanosecond } = ParseTemporalTimeString(RequireString(item)));
     RejectTime(hour, minute, second, millisecond, microsecond, nanosecond);
   }
   const TemporalPlainTime = GetIntrinsic('%Temporal.PlainTime%');
@@ -1332,7 +1351,7 @@ export function ToTemporalYearMonth(item, options) {
   }
 
   ToTemporalOverflow(options); // validate and ignore
-  let { year, month, referenceISODay, calendar } = ParseTemporalYearMonthString(ToString(item));
+  let { year, month, referenceISODay, calendar } = ParseTemporalYearMonthString(RequireString(item));
   if (calendar === undefined) calendar = 'iso8601';
   if (!IsBuiltinCalendar(calendar)) throw new RangeError(`invalid calendar identifier ${calendar}`);
   calendar = ASCIILowercase(calendar);
@@ -1453,7 +1472,7 @@ export function ToTemporalZonedDateTime(item, options) {
   } else {
     let tzName, z;
     ({ year, month, day, hour, minute, second, millisecond, microsecond, nanosecond, tzName, offset, z, calendar } =
-      ParseTemporalZonedDateTimeString(ToString(item)));
+      ParseTemporalZonedDateTimeString(RequireString(item)));
     timeZone = ToTemporalTimeZoneSlotValue(tzName);
     if (z) {
       offsetBehaviour = 'exact';
@@ -1979,7 +1998,7 @@ export function ToTemporalCalendarSlotValue(calendarLike) {
     }
     return calendarLike;
   }
-  const identifier = ToString(calendarLike);
+  const identifier = RequireString(calendarLike);
   if (IsBuiltinCalendar(identifier)) return ASCIILowercase(identifier);
   let calendar;
   try {
@@ -2098,7 +2117,7 @@ export function ToTemporalTimeZoneSlotValue(temporalTimeZoneLike) {
     }
     return temporalTimeZoneLike;
   }
-  const identifier = ToString(temporalTimeZoneLike);
+  const identifier = RequireString(temporalTimeZoneLike);
   return ParseTemporalTimeZone(identifier);
 }
 
diff --git a/polyfill/lib/timezone.mjs b/polyfill/lib/timezone.mjs
index 9796e980f6..36224634fc 100644
--- a/polyfill/lib/timezone.mjs
+++ b/polyfill/lib/timezone.mjs
@@ -20,13 +20,8 @@ import {
 } from './slots.mjs';
 
 export class TimeZone {
-  constructor(identifier) {
-    // Note: if the argument is not passed, GetCanonicalTimeZoneIdentifier(undefined) will throw.
-    //       This check exists only to improve the error message.
-    if (arguments.length < 1) {
-      throw new RangeError('missing argument: identifier is required');
-    }
-    let stringIdentifier = ES.ToString(identifier);
+  constructor(id) {
+    let stringIdentifier = ES.RequireString(id);
     if (ES.IsTimeZoneOffsetString(stringIdentifier)) {
       stringIdentifier = ES.CanonicalizeTimeZoneOffsetString(stringIdentifier);
     } else {
diff --git a/polyfill/test262 b/polyfill/test262
index c5b24c64c3..1eac172956 160000
--- a/polyfill/test262
+++ b/polyfill/test262
@@ -1 +1 @@
-Subproject commit c5b24c64c3c27544f15e1c18ef274924cff1e32c
+Subproject commit 1eac1729565c1cba26fada21d9df14f44634b93e
diff --git a/spec/abstractops.html b/spec/abstractops.html
index e68e49ac68..48f1041386 100644
--- a/spec/abstractops.html
+++ b/spec/abstractops.html
@@ -567,16 +567,21 @@ <h1>
     </emu-table>
   </emu-clause>
 
-  <emu-clause id="sec-temporal-torelativetemporalobject" aoid="ToRelativeTemporalObject">
-    <h1>ToRelativeTemporalObject ( _options_ )</h1>
-    <p>
-      The abstract operation ToRelativeTemporalObject examines the value of the `relativeTo` property of its _options_ argument.
-      If this is not present, it returns *undefined*.
-      Otherwise, it attempts to return a Temporal.ZonedDateTime instance or Temporal.PlainDate instance, in order of preference, by converting the value.
-      If neither of those are possible, the operation throws a *RangeError*.
-    </p>
+  <emu-clause id="sec-temporal-torelativetemporalobject" type="abstract operation">
+    <h1>ToRelativeTemporalObject (
+      _options_: an Object
+    ): either a normal completion containing either a Temporal.ZonedDateTime object or a Temporal.PlainDate object, or a throw completion</h1>
+    <dl class="header">
+      <dt>description</dt>
+      <dd>
+        It examines the value of the `relativeTo` property of its _options_ argument.
+        If the value is *undefined*, it returns *undefined*.
+        If the value is not a String or an Object, it throws a *TypeError*.
+        Otherwise, it attempts to return a Temporal.ZonedDateTime instance or Temporal.PlainDate instance, in order of preference, by converting the value.
+        If neither of those are possible, it throws a *RangeError*.
+      </dd>
+    </dl>
     <emu-alg>
-      1. Assert: Type(_options_) is Object.
       1. Let _value_ be ? Get(_options_, *"relativeTo"*).
       1. If _value_ is *undefined*, then
         1. Return _value_.
@@ -602,8 +607,8 @@ <h1>ToRelativeTemporalObject ( _options_ )</h1>
         1. If _offsetString_ is *undefined*, then
           1. Set _offsetBehaviour_ to ~wall~.
       1. Else,
-        1. Let _string_ be ? ToString(_value_).
-        1. Let _result_ be ? ParseTemporalRelativeToString(_string_).
+        1. If _value_ is not a String, throw a *TypeError* exception.
+        1. Let _result_ be ? ParseTemporalRelativeToString(_value_).
         1. Let _offsetString_ be _result_.[[TimeZone]].[[OffsetString]].
         1. Let _timeZoneName_ be _result_.[[TimeZone]].[[Name]].
         1. If _timeZoneName_ is *undefined*, then
@@ -1807,8 +1812,10 @@ <h1>
               1. Set _value_ to ? ToPositiveIntegerWithTruncation(_value_).
               1. Set _value_ to 𝔽(_value_).
             1. Else,
-              1. Assert: _Conversion_ is ~ToString~.
-              1. Set _value_ to ? ToString(_value_).
+              1. Assert: _Conversion_ is ~ToPrimitiveAndRequireString~.
+              1. NOTE: Non-primitive values are supported here for consistency with other fields, but such values must coerce to Strings.
+              1. Set _value_ to ? ToPrimitive(_value_, ~string~).
+              1. If _value_ is not a String, throw a *TypeError* exception.
           1. Perform ! CreateDataPropertyOrThrow(_result_, _property_, _value_).
         1. Else if _requiredFields_ is a List, then
           1. If _requiredFields_ contains _property_, then
@@ -1843,7 +1850,7 @@ <h1>
           </tr>
           <tr>
             <td>*"monthCode"*</td>
-            <td>~ToString~</td>
+            <td>~ToPrimitiveAndRequireString~</td>
             <td>*undefined*</td>
           </tr>
           <tr>
@@ -1883,12 +1890,12 @@ <h1>
           </tr>
           <tr>
             <td>*"offset"*</td>
-            <td>~ToString~</td>
+            <td>~ToPrimitiveAndRequireString~</td>
             <td>*undefined*</td>
           </tr>
           <tr>
             <td>*"era"*</td>
-            <td>~ToString~</td>
+            <td>~ToPrimitiveAndRequireString~</td>
             <td>*undefined*</td>
           </tr>
           <tr>
diff --git a/spec/calendar.html b/spec/calendar.html
index 062253ab33..eb196039d3 100644
--- a/spec/calendar.html
+++ b/spec/calendar.html
@@ -525,8 +525,8 @@ <h1>
             1. Return _temporalCalendarLike_.[[Calendar]].
           1. If ? ObjectImplementsTemporalCalendarProtocol(_temporalCalendarLike_) is *false*, throw a *TypeError* exception.
           1. Return _temporalCalendarLike_.
-        1. Let _identifier_ be ? ToString(_temporalCalendarLike_).
-        1. Set _identifier_ to ? ParseTemporalCalendarString(_identifier_).
+        1. If _temporalCalendarLike_ is not a String, throw a *TypeError* exception.
+        1. Let _identifier_ be ? ParseTemporalCalendarString(_temporalCalendarLike_).
         1. If IsBuiltinCalendar(_identifier_) is *false*, throw a *RangeError* exception.
         1. Return the ASCII-lowercase of _identifier_.
       </emu-alg>
@@ -1020,7 +1020,7 @@ <h1>Temporal.Calendar ( _id_ )</h1>
       <emu-alg>
         1. If NewTarget is *undefined*, then
           1. Throw a *TypeError* exception.
-        1. Set _id_ to ? ToString(_id_).
+        1. If _id_ is not a String, throw a *TypeError* exception.
         1. If IsBuiltinCalendar(_id_) is *false*, then
           1. Throw a *RangeError* exception.
         1. Return ? CreateTemporalCalendar(_id_, NewTarget).
diff --git a/spec/duration.html b/spec/duration.html
index 6a2ef5d75c..2aad4c2e50 100644
--- a/spec/duration.html
+++ b/spec/duration.html
@@ -932,8 +932,8 @@ <h1>
       </dl>
       <emu-alg>
         1. If Type(_temporalDurationLike_) is not Object, then
-          1. Let _string_ be ? ToString(_temporalDurationLike_).
-          1. Return ? ParseTemporalDurationString(_string_).
+          1. If _temporalDurationLike_ is not a String, throw a *TypeError* exception.
+          1. Return ? ParseTemporalDurationString(_temporalDurationLike_).
         1. If _temporalDurationLike_ has an [[InitializedTemporalDuration]] internal slot, then
           1. Return ! CreateDurationRecord(_temporalDurationLike_.[[Years]], _temporalDurationLike_.[[Months]], _temporalDurationLike_.[[Weeks]], _temporalDurationLike_.[[Days]], _temporalDurationLike_.[[Hours]], _temporalDurationLike_.[[Minutes]], _temporalDurationLike_.[[Seconds]], _temporalDurationLike_.[[Milliseconds]], _temporalDurationLike_.[[Microseconds]], _temporalDurationLike_.[[Nanoseconds]]).
         1. Let _result_ be a new Duration Record with each field set to 0.
diff --git a/spec/instant.html b/spec/instant.html
index 1445a41ba1..6a215389d9 100644
--- a/spec/instant.html
+++ b/spec/instant.html
@@ -518,8 +518,10 @@ <h1>ToTemporalInstant ( _item_ )</h1>
             1. Return _item_.
           1. If _item_ has an [[InitializedTemporalZonedDateTime]] internal slot, then
             1. Return ! CreateTemporalInstant(_item_.[[Nanoseconds]]).
-        1. Let _string_ be ? ToString(_item_).
-        1. Let _epochNanoseconds_ be ? ParseTemporalInstant(_string_).
+          1. NOTE: This use of ToPrimitive allows Instant-like objects to be converted.
+          1. Set _item_ to ? ToPrimitive(_item_, ~string~).
+        1. If _item_ is not a String, throw a *TypeError* exception.
+        1. Let _epochNanoseconds_ be ? ParseTemporalInstant(_item_).
         1. Return ! CreateTemporalInstant(_epochNanoseconds_).
       </emu-alg>
     </emu-clause>
diff --git a/spec/plaindate.html b/spec/plaindate.html
index 253fad169a..8e9ca60965 100644
--- a/spec/plaindate.html
+++ b/spec/plaindate.html
@@ -756,8 +756,8 @@ <h1>ToTemporalDate ( _item_ [ , _options_ ] )</h1>
           1. Let _fields_ be ? PrepareTemporalFields(_item_, _fieldNames_, «»).
           1. Return ? CalendarDateFromFields(_calendar_, _fields_, _options_).
         1. Perform ? ToTemporalOverflow(_options_).
-        1. Let _string_ be ? ToString(_item_).
-        1. Let _result_ be ? ParseTemporalDateString(_string_).
+        1. If _item_ is not a String, throw a *TypeError* exception.
+        1. Let _result_ be ? ParseTemporalDateString(_item_).
         1. Assert: IsValidISODate(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]) is *true*.
         1. Let _calendar_ be _result_.[[Calendar]].
         1. If _calendar_ is *undefined*, set _calendar_ to *"iso8601"*.
diff --git a/spec/plaindatetime.html b/spec/plaindatetime.html
index 94b8db76bf..8810a5381d 100644
--- a/spec/plaindatetime.html
+++ b/spec/plaindatetime.html
@@ -916,8 +916,8 @@ <h1>ToTemporalDateTime ( _item_ [ , _options_ ] )</h1>
           1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Else,
           1. Perform ? ToTemporalOverflow(_options_).
-          1. Let _string_ be ? ToString(_item_).
-          1. Let _result_ be ? ParseTemporalDateTimeString(_string_).
+          1. If _item_ is not a String, throw a *TypeError* exception.
+          1. Let _result_ be ? ParseTemporalDateTimeString(_item_).
           1. Assert: IsValidISODate(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]) is *true*.
           1. Assert: IsValidTime(_result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *true*.
           1. Let _calendar_ be _result_.[[Calendar]].
diff --git a/spec/plainmonthday.html b/spec/plainmonthday.html
index 7aaad254f8..55b5ea7b06 100644
--- a/spec/plainmonthday.html
+++ b/spec/plainmonthday.html
@@ -383,8 +383,8 @@ <h1>ToTemporalMonthDay ( _item_ [ , _options_ ] )</h1>
             1. Perform ! CreateDataPropertyOrThrow(_fields_, *"year"*, 𝔽(_referenceISOYear_)).
           1. Return ? CalendarMonthDayFromFields(_calendar_, _fields_, _options_).
         1. Perform ? ToTemporalOverflow(_options_).
-        1. Let _string_ be ? ToString(_item_).
-        1. Let _result_ be ? ParseTemporalMonthDayString(_string_).
+        1. If _item_ is not a String, throw a *TypeError* exception.
+        1. Let _result_ be ? ParseTemporalMonthDayString(_item_).
         1. Let _calendar_ be _result_.[[Calendar]].
         1. If _calendar_ is *undefined*, set _calendar_ to *"iso8601"*.
         1. If IsBuiltinCalendar(_calendar_) is *false*, throw a *RangeError* exception.
diff --git a/spec/plaintime.html b/spec/plaintime.html
index b7540f5626..60245d0829 100644
--- a/spec/plaintime.html
+++ b/spec/plaintime.html
@@ -580,8 +580,8 @@ <h1>ToTemporalTime ( _item_ [ , _overflow_ ] )</h1>
           1. Let _result_ be ? ToTemporalTimeRecord(_item_).
           1. Set _result_ to ? RegulateTime(_result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]], _overflow_).
         1. Else,
-          1. Let _string_ be ? ToString(_item_).
-          1. Let _result_ be ? ParseTemporalTimeString(_string_).
+          1. If _item_ is not a String, throw a *TypeError* exception.
+          1. Let _result_ be ? ParseTemporalTimeString(_item_).
           1. Assert: IsValidTime(_result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]) is *true*.
         1. Return ! CreateTemporalTime(_result_.[[Hour]], _result_.[[Minute]], _result_.[[Second]], _result_.[[Millisecond]], _result_.[[Microsecond]], _result_.[[Nanosecond]]).
       </emu-alg>
diff --git a/spec/plainyearmonth.html b/spec/plainyearmonth.html
index 0fe384686e..1586823e90 100644
--- a/spec/plainyearmonth.html
+++ b/spec/plainyearmonth.html
@@ -497,8 +497,8 @@ <h1>ToTemporalYearMonth ( _item_ [ , _options_ ] )</h1>
           1. Let _fields_ be ? PrepareTemporalFields(_item_, _fieldNames_, «»).
           1. Return ? CalendarYearMonthFromFields(_calendar_, _fields_, _options_).
         1. Perform ? ToTemporalOverflow(_options_).
-        1. Let _string_ be ? ToString(_item_).
-        1. Let _result_ be ? ParseTemporalYearMonthString(_string_).
+        1. If _item_ is not a String, throw a *TypeError* exception.
+        1. Let _result_ be ? ParseTemporalYearMonthString(_item_).
         1. Let _calendar_ be _result_.[[Calendar]].
         1. If _calendar_ is *undefined*, set _calendar_ to *"iso8601"*.
         1. If IsBuiltinCalendar(_calendar_) is *false*, throw a *RangeError* exception.
diff --git a/spec/timezone.html b/spec/timezone.html
index 5ad6a4e1a3..cd302892b1 100644
--- a/spec/timezone.html
+++ b/spec/timezone.html
@@ -31,7 +31,7 @@ <h1>Temporal.TimeZone ( _identifier_ )</h1>
       <emu-alg>
         1. If NewTarget is *undefined*, then
           1. Throw a *TypeError* exception.
-        1. Set _identifier_ to ? ToString(_identifier_).
+        1. If _identifier_ is not a String, throw a *TypeError* exception.
         1. If IsTimeZoneOffsetString(_identifier_) is *false*, then
           1. Let _timeZoneIdentifierRecord_ be GetAvailableNamedTimeZoneIdentifier(_identifier_).
           1. If _timeZoneIdentifierRecord_ is ~empty~, throw a *RangeError* exception.
@@ -562,8 +562,8 @@ <h1>
             1. Return _temporalTimeZoneLike_.[[TimeZone]].
           1. If ? ObjectImplementsTemporalTimeZoneProtocol(_temporalTimeZoneLike_) is *false*, throw a *TypeError* exception.
           1. Return _temporalTimeZoneLike_.
-        1. Let _identifier_ be ? ToString(_temporalTimeZoneLike_).
-        1. Let _parseResult_ be ? ParseTemporalTimeZoneString(_identifier_).
+        1. If _temporalTimeZoneLike_ is not a String, throw a *TypeError* exception.
+        1. Let _parseResult_ be ? ParseTemporalTimeZoneString(_temporalTimeZoneLike_).
         1. If _parseResult_.[[Name]] is not *undefined*, then
           1. Let _name_ be _parseResult_.[[Name]].
           1. If IsTimeZoneOffsetString(_name_) is *true*, return CanonicalizeTimeZoneOffsetString(_name_).
diff --git a/spec/zoneddatetime.html b/spec/zoneddatetime.html
index 4da9e62485..cbaa495bc3 100644
--- a/spec/zoneddatetime.html
+++ b/spec/zoneddatetime.html
@@ -1169,8 +1169,8 @@ <h1>
           1. Let _offsetOption_ be ? ToTemporalOffset(_options_, *"reject"*).
           1. Let _result_ be ? InterpretTemporalDateTimeFields(_calendar_, _fields_, _options_).
         1. Else,
-          1. Let _string_ be ? ToString(_item_).
-          1. Let _result_ be ? ParseTemporalZonedDateTimeString(_string_).
+          1. If _item_ is not a String, throw a *TypeError* exception.
+          1. Let _result_ be ? ParseTemporalZonedDateTimeString(_item_).
           1. Let _timeZoneName_ be _result_.[[TimeZone]].[[Name]].
           1. Assert: _timeZoneName_ is not *undefined*.
           1. Let _timeZone_ be ? ToTemporalTimeZoneSlotValue(_timeZoneName_).