Replace Temporal objects' .calendar getters with .calendarId/.getCalendar

This is the replacement of the old API with the new API. Semantics will be
corrected in the following commit.

Normative PR: https://github.com/tc39/proposal-temporal/pull/2482

harness/temporalHelpers.js

@@ -76,7 +76,7 @@ var TemporalHelpers = {
    * Shorthand for asserting that each field of a Temporal.PlainDate is equal to
    * an expected value. (Except the `calendar` property, since callers may want
    * to assert either object equality with an object they put in there, or the
-   * result of date.calendar.toString().)
+   * value of date.calendarId.)
    */
   assertPlainDate(date, year, month, monthCode, day, description = "", era = undefined, eraYear = undefined) {
     assert(date instanceof Temporal.PlainDate, `${description} instanceof`);
@@ -94,7 +94,7 @@ var TemporalHelpers = {
    * Shorthand for asserting that each field of a Temporal.PlainDateTime is
    * equal to an expected value. (Except the `calendar` property, since callers
    * may want to assert either object equality with an object they put in there,
-   * or the result of datetime.calendar.toString().)
+   * or the value of datetime.calendarId.)
    */
   assertPlainDateTime(datetime, year, month, monthCode, day, hour, minute, second, millisecond, microsecond, nanosecond, description = "", era = undefined, eraYear = undefined) {
     assert(datetime instanceof Temporal.PlainDateTime, `${description} instanceof`);
@@ -117,13 +117,17 @@ var TemporalHelpers = {
    *
    * Shorthand for asserting that two Temporal.PlainDateTimes are of the correct
    * type, equal according to their equals() methods, and additionally that
-   * their calendars are the same value.
+   * their calendar internal slots are the same value.
    */
   assertPlainDateTimesEqual(actual, expected, description = "") {
     assert(expected instanceof Temporal.PlainDateTime, `${description} expected value should be a Temporal.PlainDateTime`);
     assert(actual instanceof Temporal.PlainDateTime, `${description} instanceof`);
     assert(actual.equals(expected), `${description} equals method`);
-    assert.sameValue(actual.calendar, expected.calendar, `${description} calendar same value`);
+    assert.sameValue(
+      actual.getISOFields().calendar,
+      expected.getISOFields().calendar,
+      `${description} calendar same value`
+    );
   },
 
   /*
@@ -132,7 +136,7 @@ var TemporalHelpers = {
    * Shorthand for asserting that each field of a Temporal.PlainMonthDay is
    * equal to an expected value. (Except the `calendar` property, since callers
    * may want to assert either object equality with an object they put in there,
-   * or the result of monthDay.calendar.toString().)
+   * or the value of monthDay.calendarId().)
    */
   assertPlainMonthDay(monthDay, monthCode, day, description = "", referenceISOYear = 1972) {
     assert(monthDay instanceof Temporal.PlainMonthDay, `${description} instanceof`);
@@ -175,7 +179,7 @@ var TemporalHelpers = {
    * Shorthand for asserting that each field of a Temporal.PlainYearMonth is
    * equal to an expected value. (Except the `calendar` property, since callers
    * may want to assert either object equality with an object they put in there,
-   * or the result of yearMonth.calendar.toString().)
+   * or the value of yearMonth.calendarId.)
    */
   assertPlainYearMonth(yearMonth, year, month, monthCode, description = "", era = undefined, eraYear = undefined, referenceISODay = 1) {
     assert(yearMonth instanceof Temporal.PlainYearMonth, `${description} instanceof`);
@@ -192,14 +196,18 @@ var TemporalHelpers = {
    *
    * Shorthand for asserting that two Temporal.ZonedDateTimes are of the correct
    * type, equal according to their equals() methods, and additionally that
-   * their time zones and calendars are the same value.
+   * their time zones and calendar internal slots are the same value.
    */
   assertZonedDateTimesEqual(actual, expected, description = "") {
     assert(expected instanceof Temporal.ZonedDateTime, `${description} expected value should be a Temporal.ZonedDateTime`);
     assert(actual instanceof Temporal.ZonedDateTime, `${description} instanceof`);
     assert(actual.equals(expected), `${description} equals method`);
     assert.sameValue(actual.timeZone, expected.timeZone, `${description} time zone same value`);
-    assert.sameValue(actual.calendar, expected.calendar, `${description} calendar same value`);
+    assert.sameValue(
+      actual.getISOFields().calendar,
+      expected.getISOFields().calendar,
+      `${description} calendar same value`
+    );
   },
 
   /*

test/built-ins/Temporal/Calendar/from/calendar-temporal-object.js

@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = Temporal.Calendar.from(arg);
-  assert.sameValue(result, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.id, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/Calendar/prototype/dateFromFields/order-of-operations.js

@@ -42,5 +42,5 @@ const options = TemporalHelpers.propertyBagObserver(actual, {
 
 const result = instance.dateFromFields(fields, options);
 TemporalHelpers.assertPlainDate(result, 1, 1, "M01", 1, "date result");
-assert.sameValue(result.calendar, instance, "calendar result");
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot should store a string");
 assert.compareArray(actual, expected, "order of operations");

test/built-ins/Temporal/Calendar/prototype/monthDayFromFields/order-of-operations.js

@@ -42,5 +42,5 @@ const options = TemporalHelpers.propertyBagObserver(actual, {
 
 const result = instance.monthDayFromFields(fields, options);
 TemporalHelpers.assertPlainMonthDay(result, "M01", 1, "monthDay result");
-assert.sameValue(result.calendar, instance, "calendar result");
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot should store a string");
 assert.compareArray(actual, expected, "order of operations");

test/built-ins/Temporal/Calendar/prototype/yearMonthFromFields/order-of-operations.js

@@ -38,5 +38,5 @@ const options = TemporalHelpers.propertyBagObserver(actual, {
 
 const result = instance.yearMonthFromFields(fields, options);
 TemporalHelpers.assertPlainYearMonth(result, 1, 1, "M01", "yearMonth result");
-assert.sameValue(result.calendar, instance, "calendar result");
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot should store a string");
 assert.compareArray(actual, expected, "order of operations");

test/built-ins/Temporal/Duration/prototype/round/throws-in-unbalance-duration-relative-when-sign-mismatched.js

@@ -22,7 +22,7 @@ var cal = new class extends Temporal.Calendar {
 }("iso8601");
 
 var relativeTo = new Temporal.PlainDateTime(1970, 1, 1, 0, 0, 0, 0, 0, 0, cal);
-assert.sameValue(relativeTo.calendar, cal);
+assert.sameValue(relativeTo.getCalendar(), cal);
 
 var options = {
   smallestUnit: "days",

test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-case-insensitive.js

@@ -11,4 +11,4 @@ const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
 
 const arg = "iSo8601";
 const result = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-number.js

@@ -12,7 +12,7 @@ const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
 const arg = 19761118;
 
 const result = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-string-leap-second.js

@@ -12,7 +12,7 @@ const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
 let arg = "2016-12-31T23:59:60";
 const result1 = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -20,7 +20,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-string.js

@@ -12,4 +12,4 @@ const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
 const arg = "iso8601";
 
 const result = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/Instant/prototype/toZonedDateTime/calendar-temporal-object.js

@@ -33,7 +33,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
 
   const instance = new Temporal.Instant(1_000_000_000_000_000_000n);
   const result = instance.toZonedDateTime({ calendar: arg, timeZone: "UTC" });
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/Now/plainDate/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = Temporal.Now.plainDate(arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/Now/plainDate/calendar-number.js

@@ -10,7 +10,7 @@ features: [Temporal]
 const arg = 19761118;
 
 const result = Temporal.Now.plainDate(arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/Now/plainDate/calendar-string-leap-second.js

@@ -10,7 +10,7 @@ features: [Temporal]
 let arg = "2016-12-31T23:59:60";
 const result1 = Temporal.Now.plainDate(arg);
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -18,7 +18,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = Temporal.Now.plainDate(arg);
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/Now/plainDate/calendar-string.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iso8601";
 
 const result = Temporal.Now.plainDate(arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/Now/plainDate/calendar-temporal-object.js

@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = Temporal.Now.plainDate(arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/Now/plainDateISO/return-value.js

@@ -9,4 +9,4 @@ features: [Temporal]
 
 const d = Temporal.Now.plainDateISO();
 assert(d instanceof Temporal.PlainDate);
-assert.sameValue(d.calendar.id, "iso8601");
+assert.sameValue(d.getISOFields().calendar, "iso8601", "calendar slot should store a string");

test/built-ins/Temporal/Now/plainDateTime/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = Temporal.Now.plainDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/Now/plainDateTime/calendar-number.js

@@ -10,7 +10,7 @@ features: [Temporal]
 const arg = 19761118;
 
 const result = Temporal.Now.plainDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/Now/plainDateTime/calendar-string-leap-second.js

@@ -10,7 +10,7 @@ features: [Temporal]
 let arg = "2016-12-31T23:59:60";
 const result1 = Temporal.Now.plainDateTime(arg);
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -18,7 +18,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = Temporal.Now.plainDateTime(arg);
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/Now/plainDateTime/calendar-string.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iso8601";
 
 const result = Temporal.Now.plainDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/Now/plainDateTime/calendar-temporal-object.js

@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = Temporal.Now.plainDateTime(arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/Now/plainDateTimeISO/return-value-calendar.js

@@ -8,5 +8,4 @@ features: [Temporal]
 ---*/
 
 const result = Temporal.Now.plainDateTimeISO();
-assert(result.calendar instanceof Temporal.Calendar);
-assert.sameValue(result.calendar.id, "iso8601");
+assert.sameValue(result.getISOFields().calendar, "iso8601", "calendar slot should store a string");

test/built-ins/Temporal/Now/zonedDateTime/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = Temporal.Now.zonedDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/Now/zonedDateTime/calendar-number.js

@@ -10,7 +10,7 @@ features: [Temporal]
 const arg = 19761118;
 
 const result = Temporal.Now.zonedDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/Now/zonedDateTime/calendar-string-leap-second.js

@@ -10,7 +10,7 @@ features: [Temporal]
 let arg = "2016-12-31T23:59:60";
 const result1 = Temporal.Now.zonedDateTime(arg);
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -18,7 +18,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = Temporal.Now.zonedDateTime(arg);
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/Now/zonedDateTime/calendar-string.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iso8601";
 
 const result = Temporal.Now.zonedDateTime(arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/Now/zonedDateTime/calendar-temporal-object.js

@@ -6,7 +6,7 @@ esid: sec-temporal.now.zoneddatetime
 description: Fast path for converting other Temporal objects to Temporal.Calendar by reading internal slots
 info: |
     sec-temporal-totemporalcalendar step 1.b:
-      b. If _temporalCalendarLike_ has an [[InitializedTemporalDate]], [[InitializedTemporalDateTime]], [[InitializedTemporalTime]], [[InitializedTemporalMonthDay]], [[InitializedTemporalYearMonth]], or [[InitializedTemporalZonedDateTime]] internal slot, then
+      b. If _temporalCalendarLike_ has an [[InitializedTemporalDate]], [[InitializedTemporalDateTime]], [[InitializedTemporalMonthDay]], [[InitializedTemporalYearMonth]], or [[InitializedTemporalZonedDateTime]] internal slot, then
         i. Return _temporalCalendarLike_.[[Calendar]].
 includes: [compareArray.js]
 features: [Temporal]
@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = Temporal.Now.zonedDateTime(arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/Now/zonedDateTimeISO/return-value.js

@@ -10,7 +10,6 @@ features: [Temporal]
 const zdt = Temporal.Now.zonedDateTimeISO();
 const tz = Temporal.Now.timeZoneId();
 assert(zdt instanceof Temporal.ZonedDateTime);
-assert(zdt.calendar instanceof Temporal.Calendar);
-assert.sameValue(zdt.calendar.id, "iso8601");
+assert.sameValue(zdt.getISOFields().calendar, "iso8601", "calendar slot should store a string");
 assert(zdt.timeZone instanceof Temporal.TimeZone);
 assert.sameValue(zdt.timeZone.id, tz);

test/built-ins/Temporal/PlainDate/basic.js

@@ -17,9 +17,9 @@ Object.defineProperty(Temporal.Calendar, "from", {
 const calendar = new Temporal.Calendar("iso8601");
 const plainDateWithObject = new Temporal.PlainDate(2020, 12, 24, calendar);
 TemporalHelpers.assertPlainDate(plainDateWithObject, 2020, 12, "M12", 24, "with object");
-assert.sameValue(plainDateWithObject.calendar, calendar);
+assert.sameValue(plainDateWithObject.getCalendar(), calendar);
 
 const plainDateWithString = new Temporal.PlainDate(2020, 12, 24, "iso8601");
 TemporalHelpers.assertPlainDate(plainDateWithString, 2020, 12, "M12", 24, "with string");
-assert.sameValue(plainDateWithString.calendar.toString(), "iso8601");
-assert.notSameValue(plainDateWithString.calendar, calendar);
+assert.sameValue(plainDateWithString.getISOFields().calendar, "iso8601", "calendar slot should store a string");
+assert.notSameValue(plainDateWithString.getCalendar(), calendar);

test/built-ins/Temporal/PlainDate/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = new Temporal.PlainDate(2000, 5, 2, arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/PlainDate/calendar-number.js

@@ -10,7 +10,7 @@ features: [Temporal]
 const arg = 19761118;
 
 const result = new Temporal.PlainDate(2000, 5, 2, arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/PlainDate/calendar-string.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iso8601";
 
 const result = new Temporal.PlainDate(2000, 5, 2, arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/PlainDate/calendar-temporal-object.js

@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = new Temporal.PlainDate(2000, 5, 2, arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/PlainDate/calendar-undefined.js

@@ -16,7 +16,7 @@ Object.defineProperty(Temporal.Calendar, "from", {
 });
 
 const dateExplicit = new Temporal.PlainDate(...args, undefined);
-assert.sameValue(dateExplicit.calendar.toString(), "iso8601");
+assert.sameValue(dateExplicit.getISOFields().calendar, "iso8601", "calendar slot should store string");
 
 const dateImplicit = new Temporal.PlainDate(...args);
-assert.sameValue(dateImplicit.calendar.toString(), "iso8601");
+assert.sameValue(dateImplicit.getISOFields().calendar, "iso8601", "calendar slot should store string");

test/built-ins/Temporal/PlainDate/from/argument-plaindate.js

@@ -17,7 +17,7 @@ TemporalHelpers.assertPlainDate(
   "PlainDate is copied"
 );
 
-assert.sameValue(result.calendar, orig.calendar, "Calendar is copied");
+assert.sameValue(result.getISOFields().calendar, orig.getISOFields().calendar, "Calendar is copied");
 
 assert.notSameValue(
   result,

test/built-ins/Temporal/PlainDate/from/argument-plaindatetime.js

@@ -17,5 +17,5 @@ features: [Temporal]
 TemporalHelpers.checkPlainDateTimeConversionFastPath((datetime, calendar) => {
   const result = Temporal.PlainDate.from(datetime);
   TemporalHelpers.assertPlainDate(result, 2000, 5, "M05", 2);
-  assert.sameValue(result.calendar, calendar, "calendar result");
+  assert.sameValue(result.getCalendar(), calendar, "calendar result");
 });

test/built-ins/Temporal/PlainDate/from/argument-propertybag-calendar.js

@@ -11,4 +11,4 @@ features: [Temporal]
 const calendar = new Temporal.Calendar("iso8601");
 const plainDate = Temporal.PlainDate.from({ year: 1976, month: 11, day: 18, calendar });
 TemporalHelpers.assertPlainDate(plainDate, 1976, 11, "M11", 18);
-assert.sameValue(plainDate.calendar, calendar);
+assert.sameValue(plainDate.getISOFields().calendar, "iso8601", "calendar slot should store a string");

test/built-ins/Temporal/PlainDate/from/argument-zoneddatetime.js

@@ -19,7 +19,7 @@ TemporalHelpers.assertPlainDate(
 );
 
 assert.sameValue(
-  result.calendar,
+  result.getCalendar(),
   calendar,
   "Calendar is copied"
 );

test/built-ins/Temporal/PlainDate/from/calendar-temporal-object.js

@@ -22,5 +22,5 @@ features: [Temporal]
 
 TemporalHelpers.checkToTemporalCalendarFastPath((temporalObject, calendar) => {
   const result = Temporal.PlainDate.from({ year: 2000, month: 5, day: 2, calendar: temporalObject });
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getCalendar(), calendar, "Temporal object coerced to calendar");
 });

test/built-ins/Temporal/PlainDate/prototype/calendar/branding.js

@@ -1,22 +0,0 @@
-// Copyright (C) 2021 Igalia, S.L. All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-esid: sec-get-temporal.plaindate.prototype.calendar
-description: Throw a TypeError if the receiver is invalid
-features: [Symbol, Temporal]
----*/
-
-const calendar = Object.getOwnPropertyDescriptor(Temporal.PlainDate.prototype, "calendar").get;
-
-assert.sameValue(typeof calendar, "function");
-
-assert.throws(TypeError, () => calendar.call(undefined), "undefined");
-assert.throws(TypeError, () => calendar.call(null), "null");
-assert.throws(TypeError, () => calendar.call(true), "true");
-assert.throws(TypeError, () => calendar.call(""), "empty string");
-assert.throws(TypeError, () => calendar.call(Symbol()), "symbol");
-assert.throws(TypeError, () => calendar.call(1), "1");
-assert.throws(TypeError, () => calendar.call({}), "plain object");
-assert.throws(TypeError, () => calendar.call(Temporal.PlainDate), "Temporal.PlainDate");
-assert.throws(TypeError, () => calendar.call(Temporal.PlainDate.prototype), "Temporal.PlainDate.prototype");

test/built-ins/Temporal/PlainDate/prototype/calendarId/branding.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-temporal.plaindate.prototype.calendarid
+description: Throw a TypeError if the receiver is invalid
+features: [Symbol, Temporal]
+---*/
+
+const calendarId = Object.getOwnPropertyDescriptor(Temporal.PlainDate.prototype, "calendarId").get;
+
+assert.sameValue(typeof calendarId, "function");
+
+assert.throws(TypeError, () => calendarId.call(undefined), "undefined");
+assert.throws(TypeError, () => calendarId.call(null), "null");
+assert.throws(TypeError, () => calendarId.call(true), "true");
+assert.throws(TypeError, () => calendarId.call(""), "empty string");
+assert.throws(TypeError, () => calendarId.call(Symbol()), "symbol");
+assert.throws(TypeError, () => calendarId.call(1), "1");
+assert.throws(TypeError, () => calendarId.call({}), "plain object");
+assert.throws(TypeError, () => calendarId.call(Temporal.PlainDate), "Temporal.PlainDate");
+assert.throws(TypeError, () => calendarId.call(Temporal.PlainDate.prototype), "Temporal.PlainDate.prototype");

test/built-ins/Temporal/PlainDate/prototype/calendarId/prop-desc.js

@@ -2,12 +2,12 @@
 // This code is governed by the BSD license found in the LICENSE file.
 
 /*---
-esid: sec-get-temporal.plaindate.prototype.calendar
-description: The "calendar" property of Temporal.PlainDate.prototype
+esid: sec-get-temporal.plaindate.prototype.calendarid
+description: The "calendarId" property of Temporal.PlainDate.prototype
 features: [Temporal]
 ---*/
 
-const descriptor = Object.getOwnPropertyDescriptor(Temporal.PlainDate.prototype, "calendar");
+const descriptor = Object.getOwnPropertyDescriptor(Temporal.PlainDate.prototype, "calendarId");
 assert.sameValue(typeof descriptor.get, "function");
 assert.sameValue(descriptor.set, undefined);
 assert.sameValue(descriptor.enumerable, false);

test/built-ins/Temporal/PlainDate/prototype/getCalendar/branding.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: Throw a TypeError if the receiver is invalid
+features: [Symbol, Temporal]
+---*/
+
+const getCalendar = Temporal.PlainDate.prototype.getCalendar;
+
+assert.sameValue(typeof getCalendar, "function");
+
+assert.throws(TypeError, () => getCalendar.call(undefined), "undefined");
+assert.throws(TypeError, () => getCalendar.call(null), "null");
+assert.throws(TypeError, () => getCalendar.call(true), "true");
+assert.throws(TypeError, () => getCalendar.call(""), "empty string");
+assert.throws(TypeError, () => getCalendar.call(Symbol()), "symbol");
+assert.throws(TypeError, () => getCalendar.call(1), "1");
+assert.throws(TypeError, () => getCalendar.call({}), "plain object");
+assert.throws(TypeError, () => getCalendar.call(Temporal.PlainDate), "Temporal.PlainDate");
+assert.throws(TypeError, () => getCalendar.call(Temporal.PlainDate.prototype), "Temporal.PlainDate.prototype");

test/built-ins/Temporal/PlainDate/prototype/getCalendar/builtin.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: >
+    Tests that Temporal.PlainDate.prototype.getCalendar
+    meets the requirements for built-in objects defined by the
+    introduction of chapter 17 of the ECMAScript Language Specification.
+info: |
+    Built-in functions that are not constructors do not have a "prototype" property unless
+    otherwise specified in the description of a particular function.
+
+    Unless specified otherwise, a built-in object that is callable as a function is a built-in
+    function object with the characteristics described in 10.3. Unless specified otherwise, the
+    [[Extensible]] internal slot of a built-in object initially has the value true.
+
+    Unless otherwise specified every built-in function and every built-in constructor has the
+    Function prototype object [...] as the value of its [[Prototype]] internal slot.
+features: [Temporal]
+---*/
+
+assert.sameValue(Object.isExtensible(Temporal.PlainDate.prototype.getCalendar),
+  true, "Built-in objects must be extensible.");
+
+assert.sameValue(Object.prototype.toString.call(Temporal.PlainDate.prototype.getCalendar),
+  "[object Function]", "Object.prototype.toString");
+
+assert.sameValue(Object.getPrototypeOf(Temporal.PlainDate.prototype.getCalendar),
+  Function.prototype, "prototype");
+
+assert.sameValue(Temporal.PlainDate.prototype.getCalendar.hasOwnProperty("prototype"),
+  false, "prototype property");

test/built-ins/Temporal/PlainDate/prototype/getCalendar/length.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: Temporal.PlainDate.prototype.getCalendar.length is 0
+info: |
+    Every built-in function object, including constructors, has a "length" property whose value is
+    an integer. Unless otherwise specified, this value is equal to the largest number of named
+    arguments shown in the subclause headings for the function description. Optional parameters
+    (which are indicated with brackets: [ ]) or rest parameters (which are shown using the form
+    «...name») are not included in the default argument count.
+
+    Unless otherwise specified, the "length" property of a built-in function object has the
+    attributes { [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+verifyProperty(Temporal.PlainDate.prototype.getCalendar, "length", {
+  value: 0,
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDate/prototype/getCalendar/name.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: Temporal.PlainDate.prototype.getCalendar.name is "getCalendar".
+info: |
+    Every built-in function object, including constructors, that is not identified as an anonymous
+    function has a "name" property whose value is a String. Unless otherwise specified, this value
+    is the name that is given to the function in this specification.
+
+    Unless otherwise specified, the "name" property of a built-in function object, if it exists,
+    has the attributes { [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+verifyProperty(Temporal.PlainDate.prototype.getCalendar, "name", {
+  value: "getCalendar",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDate/prototype/getCalendar/not-a-constructor.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: >
+  Temporal.PlainDate.prototype.getCalendar does not implement [[Construct]], is not new-able
+info: |
+    Built-in function objects that are not identified as constructors do not implement the
+    [[Construct]] internal method unless otherwise specified in the description of a particular
+    function.
+includes: [isConstructor.js]
+features: [Reflect.construct, Temporal]
+---*/
+
+assert.throws(TypeError, () => {
+  new Temporal.PlainDate.prototype.getCalendar();
+}, "Calling as constructor");
+
+assert.sameValue(isConstructor(Temporal.PlainDate.prototype.getCalendar), false,
+  "isConstructor(Temporal.PlainDate.prototype.getCalendar)");

test/built-ins/Temporal/PlainDate/prototype/getCalendar/prop-desc.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindate.prototype.getcalendar
+description: The "getCalendar" property of Temporal.PlainDate.prototype
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+assert.sameValue(
+  typeof Temporal.PlainDate.prototype.getCalendar,
+  "function",
+  "`typeof PlainDate.prototype.getCalendar` is `function`"
+);
+
+verifyProperty(Temporal.PlainDate.prototype, "getCalendar", {
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDate/prototype/getISOFields/field-names.js

@@ -13,4 +13,4 @@ const result = date.getISOFields();
 assert.sameValue(result.isoYear, 2000, "isoYear result");
 assert.sameValue(result.isoMonth, 5, "isoMonth result");
 assert.sameValue(result.isoDay, 2, "isoDay result");
-assert.sameValue(result.calendar.id, "iso8601", "calendar result");
+assert.sameValue(result.calendar, "iso8601", "calendar result");

test/built-ins/Temporal/PlainDate/prototype/toPlainDateTime/custom.js

@@ -11,4 +11,4 @@ features: [Temporal]
 const calendar = TemporalHelpers.calendarThrowEverything();
 const plainDate = new Temporal.PlainDate(2000, 5, 2, calendar);
 const result = plainDate.toPlainDateTime("11:30:23");
-assert.sameValue(result.calendar, calendar, "calendar");
+assert.sameValue(result.getCalendar(), calendar, "calendar");

test/built-ins/Temporal/PlainDate/prototype/toPlainMonthDay/basic.js

@@ -12,4 +12,4 @@ const calendar = new Temporal.Calendar("iso8601");
 const pd = new Temporal.PlainDate(1970, 12, 24, calendar);
 const pmd = pd.toPlainMonthDay();
 TemporalHelpers.assertPlainMonthDay(pmd, "M12", 24);
-assert.sameValue(pmd.calendar, calendar);
+assert.sameValue(pmd.getISOFields().calendar, "iso8601");

test/built-ins/Temporal/PlainDate/prototype/toPlainYearMonth/basic.js

@@ -12,4 +12,4 @@ const calendar = new Temporal.Calendar("iso8601");
 const pd = new Temporal.PlainDate(1970, 12, 24, calendar);
 const pym = pd.toPlainYearMonth();
 TemporalHelpers.assertPlainYearMonth(pym, 1970, 12, "M12");
-assert.sameValue(pym.calendar, calendar);
+assert.sameValue(pym.getISOFields().calendar, "iso8601");

test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/calendar.js

@@ -16,4 +16,4 @@ const result = plainDate.toZonedDateTime({
 });
 assert.sameValue(result.epochNanoseconds, 957270600_000_000_000n);
 assert.sameValue(result.timeZone.toString(), "UTC");
-assert.sameValue(result.calendar, calendar);
+assert.sameValue(result.getCalendar(), calendar);

test/built-ins/Temporal/PlainDate/prototype/toZonedDateTime/timezone-getpossibleinstantsfor.js

@@ -13,7 +13,7 @@ class CustomTimeZone extends Temporal.TimeZone {
     super("UTC");
   }
   getPossibleInstantsFor(plainDateTime) {
-    assert.sameValue(plainDateTime.calendar, calendar);
+    assert.sameValue(plainDateTime.getCalendar(), calendar);
     return [new Temporal.Instant(987654321_000_000_000n)];
   }
 }
@@ -25,4 +25,4 @@ const result = plainDate.toZonedDateTime({
 });
 assert.sameValue(result.epochNanoseconds, 987654321_000_000_000n);
 assert.sameValue(result.timeZone, timeZone);
-assert.sameValue(result.calendar, calendar);
+assert.sameValue(result.getCalendar(), calendar);

test/built-ins/Temporal/PlainDate/prototype/withCalendar/basic.js

@@ -14,15 +14,15 @@ const calendar = Temporal.Calendar.from("iso8601");
 const objectResult = plainDate.withCalendar(calendar);
 assert.notSameValue(objectResult, plainDate, "object: new object");
 TemporalHelpers.assertPlainDate(objectResult, 1976, 11, "M11", 18, "object");
-assert.sameValue(objectResult.calendar, calendar, "object: calendar");
+assert.sameValue(objectResult.getCalendar(), calendar, "object: calendar");
 
 const stringResult = plainDate.withCalendar("iso8601");
 assert.notSameValue(stringResult, plainDate, "string: new object");
 TemporalHelpers.assertPlainDate(stringResult, 1976, 11, "M11", 18, "string");
-assert.sameValue(stringResult.calendar.id, "iso8601", "string: calendar");
+assert.sameValue(stringResult.getISOFields().calendar, "iso8601", "string: calendar slot stores a string");
 
-const originalCalendar = plainDate.calendar;
+const originalCalendar = plainDate.getCalendar();
 const sameResult = plainDate.withCalendar(originalCalendar);
 assert.notSameValue(sameResult, plainDate, "original: new object");
 TemporalHelpers.assertPlainDate(sameResult, 1976, 11, "M11", 18, "original");
-assert.sameValue(sameResult.calendar, originalCalendar, "original: calendar");
+assert.sameValue(sameResult.getCalendar(), originalCalendar, "original: calendar slot stores and object");

test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-case-insensitive.js

@@ -11,4 +11,4 @@ const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
 
 const arg = "iSo8601";
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-number.js

@@ -12,7 +12,7 @@ const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
 const arg = 19761118;
 
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-string-leap-second.js

@@ -12,7 +12,7 @@ const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
 let arg = "2016-12-31T23:59:60";
 const result1 = instance.withCalendar(arg);
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -20,7 +20,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = instance.withCalendar(arg);
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-string.js

@@ -12,4 +12,4 @@ const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
 const arg = "iso8601";
 
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/PlainDate/prototype/withCalendar/calendar-temporal-object.js

@@ -33,7 +33,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
 
   const instance = new Temporal.PlainDate(1976, 11, 18, { id: "replace-me" });
   const result = instance.withCalendar(arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/PlainDate/prototype/withCalendar/subclassing-ignored.js

@@ -25,6 +25,6 @@ TemporalHelpers.checkSubclassingIgnored(
   [customCalendar],
   (result) => {
     TemporalHelpers.assertPlainDate(result, 1900, 2, "M02", 5);
-    assert.sameValue(result.calendar, customCalendar, "calendar result");
+    assert.sameValue(result.getCalendar(), customCalendar, "calendar result");
   },
 );

test/built-ins/Temporal/PlainDateTime/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = new Temporal.PlainDateTime(2000, 5, 2, 15, 23, 30, 987, 654, 321, arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/PlainDateTime/calendar-number.js

@@ -10,7 +10,7 @@ features: [Temporal]
 const arg = 19761118;
 
 const result = new Temporal.PlainDateTime(2000, 5, 2, 15, 23, 30, 987, 654, 321, arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/PlainDateTime/calendar-string.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iso8601";
 
 const result = new Temporal.PlainDateTime(2000, 5, 2, 15, 23, 30, 987, 654, 321, arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/PlainDateTime/calendar-temporal-object.js

@@ -32,7 +32,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
   });
 
   const result = new Temporal.PlainDateTime(2000, 5, 2, 15, 23, 30, 987, 654, 321, arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/PlainDateTime/calendar-undefined.js

@@ -16,7 +16,7 @@ Object.defineProperty(Temporal.Calendar, "from", {
 });
 
 const dateTimeExplicit = new Temporal.PlainDateTime(...dateTimeArgs, undefined);
-assert.sameValue(dateTimeExplicit.calendar.toString(), "iso8601");
+assert.sameValue(dateTimeExplicit.calendarId, "iso8601");
 
 const dateTimeImplicit = new Temporal.PlainDateTime(...dateTimeArgs);
-assert.sameValue(dateTimeImplicit.calendar.toString(), "iso8601");
+assert.sameValue(dateTimeImplicit.calendarId, "iso8601");

test/built-ins/Temporal/PlainDateTime/constructor-full.js

@@ -17,7 +17,7 @@ TemporalHelpers.assertPlainDateTime(datetime,
 );
 
 assert.sameValue(
-  datetime.calendar,
+  datetime.getCalendar(),
   calendar,
   "calendar supplied in constructor can be extracted and is unchanged"
 );

test/built-ins/Temporal/PlainDateTime/from/argument-plaindate.js

@@ -17,5 +17,5 @@ features: [Temporal]
 TemporalHelpers.checkToTemporalPlainDateTimeFastPath((date, calendar) => {
   const result = Temporal.PlainDateTime.from(date);
   TemporalHelpers.assertPlainDateTime(result, 2000, 5, "M05", 2, 0, 0, 0, 0, 0, 0, "midnight is assumed");
-  assert.sameValue(result.calendar, calendar, "calendar result");
+  assert.sameValue(result.getCalendar(), calendar, "calendar result");
 });

test/built-ins/Temporal/PlainDateTime/from/argument-plaindatetime.js

@@ -17,7 +17,7 @@ TemporalHelpers.assertPlainDateTime(
   "PlainDateTime is copied"
 );
 
-assert.sameValue(result.calendar, orig.calendar, "Calendar is copied");
+assert.sameValue(result.getISOFields().calendar, orig.getISOFields().calendar, "Calendar is copied");
 
 assert.notSameValue(
   result,

test/built-ins/Temporal/PlainDateTime/from/calendar-temporal-object.js

@@ -22,5 +22,5 @@ features: [Temporal]
 
 TemporalHelpers.checkToTemporalCalendarFastPath((temporalObject, calendar) => {
   const result = Temporal.PlainDateTime.from({ year: 2000, month: 5, day: 2, calendar: temporalObject });
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getCalendar(), calendar, "Temporal object coerced to calendar");
 });

test/built-ins/Temporal/PlainDateTime/prototype/calendar/branding.js

@@ -1,22 +0,0 @@
-// Copyright (C) 2021 Igalia, S.L. All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-
-/*---
-esid: sec-get-temporal.plaindatetime.prototype.calendar
-description: Throw a TypeError if the receiver is invalid
-features: [Symbol, Temporal]
----*/
-
-const calendar = Object.getOwnPropertyDescriptor(Temporal.PlainDateTime.prototype, "calendar").get;
-
-assert.sameValue(typeof calendar, "function");
-
-assert.throws(TypeError, () => calendar.call(undefined), "undefined");
-assert.throws(TypeError, () => calendar.call(null), "null");
-assert.throws(TypeError, () => calendar.call(true), "true");
-assert.throws(TypeError, () => calendar.call(""), "empty string");
-assert.throws(TypeError, () => calendar.call(Symbol()), "symbol");
-assert.throws(TypeError, () => calendar.call(1), "1");
-assert.throws(TypeError, () => calendar.call({}), "plain object");
-assert.throws(TypeError, () => calendar.call(Temporal.PlainDateTime), "Temporal.PlainDateTime");
-assert.throws(TypeError, () => calendar.call(Temporal.PlainDateTime.prototype), "Temporal.PlainDateTime.prototype");

test/built-ins/Temporal/PlainDateTime/prototype/calendarId/branding.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2022 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-get-temporal.plaindatetime.prototype.calendarid
+description: Throw a TypeError if the receiver is invalid
+features: [Symbol, Temporal]
+---*/
+
+const calendarId = Object.getOwnPropertyDescriptor(Temporal.PlainDateTime.prototype, "calendarId").get;
+
+assert.sameValue(typeof calendarId, "function");
+
+assert.throws(TypeError, () => calendarId.call(undefined), "undefined");
+assert.throws(TypeError, () => calendarId.call(null), "null");
+assert.throws(TypeError, () => calendarId.call(true), "true");
+assert.throws(TypeError, () => calendarId.call(""), "empty string");
+assert.throws(TypeError, () => calendarId.call(Symbol()), "symbol");
+assert.throws(TypeError, () => calendarId.call(1), "1");
+assert.throws(TypeError, () => calendarId.call({}), "plain object");
+assert.throws(TypeError, () => calendarId.call(Temporal.PlainDateTime), "Temporal.PlainDateTime");
+assert.throws(TypeError, () => calendarId.call(Temporal.PlainDateTime.prototype), "Temporal.PlainDateTime.prototype");

test/built-ins/Temporal/PlainDateTime/prototype/calendarId/prop-desc.js

@@ -2,12 +2,12 @@
 // This code is governed by the BSD license found in the LICENSE file.
 
 /*---
-esid: sec-get-temporal.plainyearmonth.prototype.calendar
-description: The "calendar" property of Temporal.PlainYearMonth.prototype
+esid: sec-get-temporal.plaindatetime.prototype.calendarid
+description: The "calendarId" property of Temporal.PlainDateTime.prototype
 features: [Temporal]
 ---*/
 
-const descriptor = Object.getOwnPropertyDescriptor(Temporal.PlainYearMonth.prototype, "calendar");
+const descriptor = Object.getOwnPropertyDescriptor(Temporal.PlainDateTime.prototype, "calendarId");
 assert.sameValue(typeof descriptor.get, "function");
 assert.sameValue(descriptor.set, undefined);
 assert.sameValue(descriptor.enumerable, false);

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/branding.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: Throw a TypeError if the receiver is invalid
+features: [Symbol, Temporal]
+---*/
+
+const getCalendar = Temporal.PlainDateTime.prototype.getCalendar;
+
+assert.sameValue(typeof getCalendar, "function");
+
+assert.throws(TypeError, () => getCalendar.call(undefined), "undefined");
+assert.throws(TypeError, () => getCalendar.call(null), "null");
+assert.throws(TypeError, () => getCalendar.call(true), "true");
+assert.throws(TypeError, () => getCalendar.call(""), "empty string");
+assert.throws(TypeError, () => getCalendar.call(Symbol()), "symbol");
+assert.throws(TypeError, () => getCalendar.call(1), "1");
+assert.throws(TypeError, () => getCalendar.call({}), "plain object");
+assert.throws(TypeError, () => getCalendar.call(Temporal.PlainDateTime), "Temporal.PlainDateTime");
+assert.throws(TypeError, () => getCalendar.call(Temporal.PlainDateTime.prototype), "Temporal.PlainDateTime.prototype");

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/builtin.js

@@ -0,0 +1,33 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: >
+    Tests that Temporal.PlainDateTime.prototype.getCalendar
+    meets the requirements for built-in objects defined by the
+    introduction of chapter 17 of the ECMAScript Language Specification.
+info: |
+    Built-in functions that are not constructors do not have a "prototype" property unless
+    otherwise specified in the description of a particular function.
+
+    Unless specified otherwise, a built-in object that is callable as a function is a built-in
+    function object with the characteristics described in 10.3. Unless specified otherwise, the
+    [[Extensible]] internal slot of a built-in object initially has the value true.
+
+    Unless otherwise specified every built-in function and every built-in constructor has the
+    Function prototype object [...] as the value of its [[Prototype]] internal slot.
+features: [Temporal]
+---*/
+
+assert.sameValue(Object.isExtensible(Temporal.PlainDateTime.prototype.getCalendar),
+  true, "Built-in objects must be extensible.");
+
+assert.sameValue(Object.prototype.toString.call(Temporal.PlainDateTime.prototype.getCalendar),
+  "[object Function]", "Object.prototype.toString");
+
+assert.sameValue(Object.getPrototypeOf(Temporal.PlainDateTime.prototype.getCalendar),
+  Function.prototype, "prototype");
+
+assert.sameValue(Temporal.PlainDateTime.prototype.getCalendar.hasOwnProperty("prototype"),
+  false, "prototype property");

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/length.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: Temporal.PlainDateTime.prototype.getCalendar.length is 0
+info: |
+    Every built-in function object, including constructors, has a "length" property whose value is
+    an integer. Unless otherwise specified, this value is equal to the largest number of named
+    arguments shown in the subclause headings for the function description. Optional parameters
+    (which are indicated with brackets: [ ]) or rest parameters (which are shown using the form
+    «...name») are not included in the default argument count.
+
+    Unless otherwise specified, the "length" property of a built-in function object has the
+    attributes { [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+verifyProperty(Temporal.PlainDateTime.prototype.getCalendar, "length", {
+  value: 0,
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/name.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: Temporal.PlainDateTime.prototype.getCalendar.name is "getCalendar".
+info: |
+    Every built-in function object, including constructors, that is not identified as an anonymous
+    function has a "name" property whose value is a String. Unless otherwise specified, this value
+    is the name that is given to the function in this specification.
+
+    Unless otherwise specified, the "name" property of a built-in function object, if it exists,
+    has the attributes { [[Writable]]: false, [[Enumerable]]: false, [[Configurable]]: true }.
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+verifyProperty(Temporal.PlainDateTime.prototype.getCalendar, "name", {
+  value: "getCalendar",
+  writable: false,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/not-a-constructor.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2021 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: >
+  Temporal.PlainDateTime.prototype.getCalendar does not implement [[Construct]], is not new-able
+info: |
+    Built-in function objects that are not identified as constructors do not implement the
+    [[Construct]] internal method unless otherwise specified in the description of a particular
+    function.
+includes: [isConstructor.js]
+features: [Reflect.construct, Temporal]
+---*/
+
+assert.throws(TypeError, () => {
+  new Temporal.PlainDateTime.prototype.getCalendar();
+}, "Calling as constructor");
+
+assert.sameValue(isConstructor(Temporal.PlainDateTime.prototype.getCalendar), false,
+  "isConstructor(Temporal.PlainDateTime.prototype.getCalendar)");

test/built-ins/Temporal/PlainDateTime/prototype/getCalendar/prop-desc.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2023 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.plaindatetime.prototype.getcalendar
+description: The "getCalendar" property of Temporal.PlainDateTime.prototype
+includes: [propertyHelper.js]
+features: [Temporal]
+---*/
+
+assert.sameValue(
+  typeof Temporal.PlainDateTime.prototype.getCalendar,
+  "function",
+  "`typeof PlainDateTime.prototype.getCalendar` is `function`"
+);
+
+verifyProperty(Temporal.PlainDateTime.prototype, "getCalendar", {
+  writable: true,
+  enumerable: false,
+  configurable: true,
+});

test/built-ins/Temporal/PlainDateTime/prototype/getISOFields/field-names.js

@@ -19,4 +19,4 @@ assert.sameValue(result.isoSecond, 56, "isoSecond result");
 assert.sameValue(result.isoMillisecond, 987, "isoMillisecond result");
 assert.sameValue(result.isoMicrosecond, 654, "isoMicrosecond result");
 assert.sameValue(result.isoNanosecond, 321, "isoNanosecond result");
-assert.sameValue(result.calendar.id, "iso8601", "calendar result");
+assert.sameValue(result.calendar, "iso8601", "calendar result");

test/built-ins/Temporal/PlainDateTime/prototype/since/calendar-dateuntil-called-with-plaindate-calendar.js

@@ -19,8 +19,8 @@ class Calendar extends Temporal.Calendar {
   }
 
   dateUntil(d1, d2) {
-    assert.sameValue(d1.calendar, this, "d1.calendar");
-    assert.sameValue(d2.calendar, this, "d2.calendar");
+    assert.sameValue(d1.getCalendar(), this, "d1.calendar");
+    assert.sameValue(d2.getCalendar(), this, "d2.calendar");
     return new Temporal.Duration();
   }
 }

test/built-ins/Temporal/PlainDateTime/prototype/toZonedDateTime/basic.js

@@ -11,5 +11,5 @@ const dt = new Temporal.PlainDateTime(2020, 1, 1, 0, 0);
 const zdt = dt.toZonedDateTime("UTC");
 
 assert.sameValue(zdt.epochNanoseconds, 1577836800000000000n, "nanoseconds");
-assert.sameValue(zdt.calendar.toString(), "iso8601", "calendar");
+assert.sameValue(zdt.calendarId, "iso8601", "calendar");
 assert.sameValue(zdt.timeZone.toString(), "UTC", "timezone");

test/built-ins/Temporal/PlainDateTime/prototype/toZonedDateTime/plain-custom-timezone.js

@@ -40,6 +40,6 @@ const timeZone = TemporalHelpers.timeZoneObserver(actual, "timeZone", {
 const result = dateTime.toZonedDateTime(timeZone, options);
 assert.sameValue(result.epochNanoseconds, instant.epochNanoseconds);
 assert.sameValue(result.timeZone, timeZone);
-assert.sameValue(result.calendar, dateTime.calendar);
-
 assert.compareArray(actual, expected);
+
+assert.sameValue(result.getISOFields().calendar, dateTime.getISOFields().calendar);

test/built-ins/Temporal/PlainDateTime/prototype/until/calendar-dateuntil-called-with-plaindate-calendar.js

@@ -19,8 +19,8 @@ class Calendar extends Temporal.Calendar {
   }
 
   dateUntil(d1, d2) {
-    assert.sameValue(d1.calendar, this, "d1.calendar");
-    assert.sameValue(d2.calendar, this, "d2.calendar");
+    assert.sameValue(d1.getCalendar(), this, "d1.calendar");
+    assert.sameValue(d2.getCalendar(), this, "d2.calendar");
     return new Temporal.Duration();
   }
 }

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/basic.js

@@ -19,4 +19,4 @@ TemporalHelpers.assertPlainDateTime(
   "works"
 );
 
-assert.sameValue(result.calendar, calendar, "underlying calendar is unchanged");
+assert.sameValue(result.getCalendar(), calendar, "underlying calendar is unchanged");

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-case-insensitive.js

@@ -11,4 +11,4 @@ const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456,
 
 const arg = "iSo8601";
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-number.js

@@ -12,7 +12,7 @@ const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456,
 const arg = 19761118;
 
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", "19761118 is a valid ISO string for Calendar");
+assert.sameValue(result.calendarId, "iso8601", "19761118 is a valid ISO string for Calendar");
 
 const numbers = [
   1,

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-string-leap-second.js

@@ -12,7 +12,7 @@ const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456,
 let arg = "2016-12-31T23:59:60";
 const result1 = instance.withCalendar(arg);
 assert.sameValue(
-  result1.calendar.id,
+  result1.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar"
 );
@@ -20,7 +20,7 @@ assert.sameValue(
 arg = { calendar: "2016-12-31T23:59:60" };
 const result2 = instance.withCalendar(arg);
 assert.sameValue(
-  result2.calendar.id,
+  result2.calendarId,
   "iso8601",
   "leap second is a valid ISO string for Calendar (nested property)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-string.js

@@ -12,4 +12,4 @@ const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456,
 const arg = "iso8601";
 
 const result = instance.withCalendar(arg);
-assert.sameValue(result.calendar.id, "iso8601", `Calendar created from string "${arg}"`);
+assert.sameValue(result.getISOFields().calendar, "iso8601", `Calendar created from string "${arg}"`);

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/calendar-temporal-object.js

@@ -33,7 +33,7 @@ const zonedDateTime = new Temporal.ZonedDateTime(1_000_000_000_000_000_000n, "UT
 
   const instance = new Temporal.PlainDateTime(1976, 11, 18, 15, 23, 30, 123, 456, 789, { id: "replace-me" });
   const result = instance.withCalendar(arg);
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getISOFields().calendar, calendar, "Temporal object coerced to calendar");
 
   assert.compareArray(actual, expected, "calendar getter not called");
 });

test/built-ins/Temporal/PlainDateTime/prototype/withCalendar/subclassing-ignored.js

@@ -25,6 +25,6 @@ TemporalHelpers.checkSubclassingIgnored(
   [customCalendar],
   (result) => {
     TemporalHelpers.assertPlainDateTime(result, 1900, 2, "M02", 5, 12, 34, 56, 987, 654, 321);
-    assert.sameValue(result.calendar, customCalendar, "calendar result");
+    assert.sameValue(result.getCalendar(), customCalendar, "calendar result");
   },
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-plaindate-calendar-noniso.js

@@ -19,7 +19,7 @@ const cal = {
   day() { return 6; }
 };
 const pdt = new Temporal.PlainDateTime(1995, 12, 7, 3, 24, 30, 0, 0, 0);
-assert.sameValue(pdt.calendar.toString(), "iso8601", "PlainDateTime with ISO calendar");
+assert.sameValue(pdt.calendarId, "iso8601", "PlainDateTime with ISO calendar");
 const pd = new Temporal.PlainDate(2010, 11, 12, cal);
 const shifted = pdt.withPlainDate(pd);
 
@@ -31,7 +31,7 @@ TemporalHelpers.assertPlainDateTime(
 );
 
 assert.sameValue(
-  shifted.calendar,
+  shifted.getCalendar(),
   cal,
   "calendar is changed if receiver has ISO calendar (2)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-plaindate-calendar-same-id.js

@@ -33,7 +33,7 @@ TemporalHelpers.assertPlainDateTime(
 );
 
 assert.sameValue(
-  shifted.calendar,
+  shifted.getCalendar(),
   cal2,
   "calendar is changed with same id (2)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-plaindate-calendar-same-object.js

@@ -34,7 +34,7 @@ TemporalHelpers.assertPlainDateTime(
 );
 
 assert.sameValue(
-  shifted.calendar,
+  shifted.getCalendar(),
   cal,
   "calendar is unchanged with same calendars (2)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-plaindate-calendar.js

@@ -20,7 +20,7 @@ const cal = {
 };
 const pdt = new Temporal.PlainDateTime(1995, 12, 7, 3, 24, 30, 0, 0, 0, cal);
 const pd = new Temporal.PlainDate(2010, 11, 12);
-assert.sameValue(pd.calendar.toString(), "iso8601", "PlainDate with ISO calendar");
+assert.sameValue(pd.calendarId, "iso8601", "PlainDate with ISO calendar");
 const shifted = pdt.withPlainDate(pd);
 
 TemporalHelpers.assertPlainDateTime(
@@ -31,7 +31,7 @@ TemporalHelpers.assertPlainDateTime(
 );
 
 assert.sameValue(
-  shifted.calendar,
+  shifted.getCalendar(),
   cal,
   "calendar is unchanged if input has ISO calendar (2)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/argument-string-iso-calendar.js

@@ -29,7 +29,7 @@ TemporalHelpers.assertPlainDateTime(
 );
 
 assert.sameValue(
-  shifted.calendar,
+  shifted.getCalendar(),
   cal,
   "calendar is unchanged if input has ISO calendar (2)"
 );

test/built-ins/Temporal/PlainDateTime/prototype/withPlainDate/calendar-temporal-object.js

@@ -24,5 +24,5 @@ TemporalHelpers.checkToTemporalCalendarFastPath((temporalObject, calendar) => {
   const datetime = new Temporal.PlainDateTime(2000, 5, 3, 13, 3, 27, 123, 456, 789);
   // the PlainDate's calendar will override the PlainDateTime's ISO calendar
   const result = datetime.withPlainDate({ year: 2001, month: 6, day: 4, calendar: temporalObject });
-  assert.sameValue(result.calendar, calendar, "Temporal object coerced to calendar");
+  assert.sameValue(result.getCalendar(), calendar, "Temporal object coerced to calendar");
 });

test/built-ins/Temporal/PlainMonthDay/basic.js

@@ -10,12 +10,12 @@ features: [Temporal]
 
 const leapDay = new Temporal.PlainMonthDay(2, 29);
 TemporalHelpers.assertPlainMonthDay(leapDay, "M02", 29, "leap day is supported");
-assert.sameValue(leapDay.calendar.id, "iso8601", "leap day calendar");
+assert.sameValue(leapDay.calendarId, "iso8601", "leap day calendar");
 
 const beforeEpoch = new Temporal.PlainMonthDay(12, 2, "iso8601", 1920);
 TemporalHelpers.assertPlainMonthDay(beforeEpoch, "M12", 2, "reference year before epoch", 1920);
-assert.sameValue(beforeEpoch.calendar.id, "iso8601", "reference year before epoch calendar");
+assert.sameValue(beforeEpoch.calendarId, "iso8601", "reference year before epoch calendar");
 
 const afterEpoch = new Temporal.PlainMonthDay(1, 7, "iso8601", 1980);
 TemporalHelpers.assertPlainMonthDay(afterEpoch, "M01", 7, "reference year after epoch", 1980);
-assert.sameValue(afterEpoch.calendar.id, "iso8601", "reference year after epoch calendar");
+assert.sameValue(afterEpoch.calendarId, "iso8601", "reference year after epoch calendar");

test/built-ins/Temporal/PlainMonthDay/calendar-case-insensitive.js

@@ -10,4 +10,4 @@ features: [Temporal]
 const arg = "iSo8601";
 
 const result = new Temporal.PlainMonthDay(12, 15, arg, 1972);
-assert.sameValue(result.calendar.id, "iso8601", "Calendar is case-insensitive");
+assert.sameValue(result.calendarId, "iso8601", "Calendar is case-insensitive");