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diff --git a/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/mergeFields/order-of-operations.js b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/mergeFields/order-of-operations.js
new file mode 100644
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+++ b/js/src/tests/test262/built-ins/Temporal/Calendar/prototype/mergeFields/order-of-operations.js
@@ -0,0 +1,50 @@
+// |reftest| skip-if(!this.hasOwnProperty('Temporal')) -- Temporal is not enabled unconditionally
+// Copyright (C) 2022 Igalia S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.calendar.prototype.mergefields
+description: Properties on objects passed to mergeFields() are accessed in the correct order
+features: [Temporal]
+includes: [compareArray.js, temporalHelpers.js]
+---*/
+
+const expected = [
+  // CopyDataProperties on fields
+  "ownKeys fields",
+  "getOwnPropertyDescriptor fields.year",
+  "get fields.year",
+  "getOwnPropertyDescriptor fields.month",
+  "get fields.month",
+  "getOwnPropertyDescriptor fields.day",
+  "get fields.day",
+  "getOwnPropertyDescriptor fields.extra",
+  "get fields.extra",
+  // CopyDataProperties on additionalFields
+  "ownKeys additionalFields",
+  "getOwnPropertyDescriptor additionalFields[3]",
+  "get additionalFields[3]",
+  "getOwnPropertyDescriptor additionalFields.monthCode",
+  "get additionalFields.monthCode",
+  "getOwnPropertyDescriptor additionalFields[Symbol('extra')]",
+  "get additionalFields[Symbol('extra')]",
+];
+const actual = [];
+
+const fields = TemporalHelpers.propertyBagObserver(actual, {
+  year: 2022,
+  month: 10,
+  day: 17,
+  extra: "extra property",
+}, "fields");
+const additionalFields = TemporalHelpers.propertyBagObserver(actual, {
+  [Symbol("extra")]: "extra symbol property",
+  monthCode: "M10",
+  3: "extra array index property",
+}, "additionalFields");
+
+const instance = new Temporal.Calendar("iso8601");
+instance.mergeFields(fields, additionalFields);
+assert.compareArray(actual, expected, "order of observable operations");
+
+reportCompare(0, 0);