1 files changed, 38 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.matchAll/this-lastindex-cached.js b/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.matchAll/this-lastindex-cached.js
new file mode 100644
index 0000000000..0c669c3594
--- /dev/null
+++ b/js/src/tests/test262/built-ins/RegExp/prototype/Symbol.matchAll/this-lastindex-cached.js
@@ -0,0 +1,38 @@
+// Copyright (C) 2018 Peter Wong. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: pending
+description: Verify regexp's lastIndex is cached
+info: |
+  RegExp.prototype [ @@matchAll ] ( string )
+    [...]
+    3. Return ? MatchAllIterator(R, string).
+
+  MatchAllIterator ( R, O )
+    [...]
+    2. If ? IsRegExp(R) is true, then
+      [...]
+      f. Let lastIndex be ? ToLength(? Get(R, "lastIndex")).
+      g. Perform ? Set(matcher, "lastIndex", lastIndex, true).
+features: [Symbol.matchAll]
+includes: [compareArray.js, compareIterator.js, regExpUtils.js]
+---*/
+
+var regexp = /./g;
+regexp.lastIndex = {
+  valueOf() {
+    return 2;
+  }
+};
+var str = 'abcd';
+var iter = regexp[Symbol.matchAll](str);
+
+// Verify lastIndex is cached at the time of calling @@matchAll
+regexp.lastIndex = 0;
+
+assert.compareIterator(iter, [
+  matchValidator(['c'], 2, str),
+  matchValidator(['d'], 3, str)
+]);
+
+reportCompare(0, 0);