1 files changed, 73 insertions, 0 deletions
diff --git a/deps/v8/test/mjsunit/array-lastindexof.js b/deps/v8/test/mjsunit/array-lastindexof.js
index 785bd64727a..c31ad18b55d 100644
--- a/deps/v8/test/mjsunit/array-lastindexof.js
+++ b/deps/v8/test/mjsunit/array-lastindexof.js
@@ -8,3 +8,76 @@ assertThrows(() => {
 assertThrows(() => {
   Array.prototype.lastIndexOf.call(undefined, 42);
 }, TypeError);
+
+/* Tests inspired by test262's
+  lastIndexOf/calls-only-has-on-prototype-after-length-zeroed.js */
+// Stateful fromIndex that tries to empty the array
+(function testFromIndex() {
+  var array = [5, undefined, 7];
+  var fromIndex = {
+    valueOf: function() {
+      array.length = 1;
+      return 2;
+    }
+  };
+  assertEquals(-1, array.lastIndexOf(undefined, fromIndex));
+
+  array = [5, undefined, 7];
+  assertEquals(0, array.lastIndexOf(5, fromIndex));
+})();
+
+// Stateful fromIndex and proxy as Prototype
+// Must test for [[HasProperty]] before [[Get]]
+var testHasProperty = function(value) {
+  var array = [5, undefined, 7];
+  var fromIndex = {
+    valueOf: function() {
+      array.length = 0;
+      return 2;
+    }
+  };
+
+  // Install a prototype that only has [[HasProperty]], and throws on [[Get]]
+  Object.setPrototypeOf(array,
+    new Proxy(Array.prototype, {
+                has: function(t, pk) { return pk in t; },
+                get: function () { throw new Error('[[Get]] trap called') },
+              }));
+
+  assertEquals(-1, Array.prototype.lastIndexOf.call(array, value, fromIndex));
+}
+
+testHasProperty(5);
+testHasProperty(undefined);
+
+// Test call order: [[HasProperty]] before [[Get]]
+var testHasPropertyThenGet = function(value) {
+  var array = [5, , 7];
+  var log = [];
+
+  // Install a prototype with only [[HasProperty]] and [[Get]]
+  Object.setPrototypeOf(array,
+    new Proxy(Array.prototype, {
+                has: function() { log.push("HasProperty"); return true; },
+                get: function() { log.push("Get"); },
+              }));
+  // The 2nd element (index 1) will trigger the calls to the prototype
+  Array.prototype.lastIndexOf.call(array, value);
+  assertEquals(["HasProperty", "Get"], log);
+}
+
+testHasPropertyThenGet(5);
+testHasPropertyThenGet(undefined);
+
+// Test for sparse Arrays
+/* This will not enter the fast path for sparse arrays, due to UseSparseVariant
+  excluding array elements with accessors */
+(function() {
+  var array = new Array(10000);
+  array[0] = 5; array[9999] = 7;
+
+  var count = 0;
+  Object.defineProperty(array.__proto__, 9998, { get: () => ++count });
+  Array.prototype.lastIndexOf.call(array, 0);
+  assertEquals(1,count);
+})();