Improve coverage of mapped arguments' [[DefineOwnProperty]] method

test/language/arguments-object/mapped/enumerable-configurable-accessor-descriptor.js

@@ -0,0 +1,44 @@
+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-arguments-exotic-objects-defineownproperty-p-desc
+description: >
+  Index gets unmapped when redefined with accessor. Unmapped index is created.
+info: |
+  [[DefineOwnProperty]] ( P, Desc )
+
+  [...]
+  6. Let allowed be ? OrdinaryDefineOwnProperty(args, P, newArgDesc).
+  7. If allowed is false, return false.
+  8. If isMapped is true, then
+    a. If IsAccessorDescriptor(Desc) is true, then
+      i. Call map.[[Delete]](P).
+    [...]
+  9. Return true.
+flags: [noStrict]
+---*/
+
+(function(a) {
+  let setCalls = 0;
+  Object.defineProperty(arguments, "0", {
+    set(_v) { setCalls += 1; },
+    enumerable: true,
+    configurable: true,
+  });
+
+  arguments[0] = "foo";
+
+  assert.sameValue(setCalls, 1);
+  assert.sameValue(a, 0);
+  assert.sameValue(arguments[0], undefined);
+
+
+  Object.defineProperty(arguments, "1", {
+    get: () => "bar",
+    enumerable: true,
+    configurable: true,
+  });
+
+  assert.sameValue(arguments[1], "bar");
+})(0);

test/language/arguments-object/mapped/nonconfigurable-descriptors-define-failure.js

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+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-arguments-exotic-objects-defineownproperty-p-desc
+description: >
+  OrdinaryDefineOwnProperty returning `false` doesn't leave `arguments` in a
+  corrupted state, for both mapped and unmapped indices.
+info: |
+  [[DefineOwnProperty]] ( P, Desc )
+
+  [...]
+  6. Let allowed be ? OrdinaryDefineOwnProperty(args, P, newArgDesc).
+  7. If allowed is false, return false.
+flags: [noStrict]
+---*/
+
+(function(a) {
+  Object.defineProperty(arguments, "0", {configurable: false});
+
+  assert.throws(TypeError, () => {
+    Object.defineProperty(arguments, "0", {configurable: true});
+  });
+
+  a = 2;
+  assert.sameValue(arguments[0], 2);
+
+
+  Object.defineProperty(arguments, "1", {
+    get: () => 3,
+    configurable: false,
+  });
+
+  assert.throws(TypeError, () => {
+    Object.defineProperty(arguments, "1", {value: "foo"});
+  });
+
+  assert.sameValue(arguments[1], 3);
+  assert.throws(TypeError, () => {
+    "use strict";
+    delete arguments[1];
+  });
+})(0);

test/language/arguments-object/mapped/writable-enumerable-configurable-descriptor.js

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+// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-arguments-exotic-objects-defineownproperty-p-desc
+description: >
+  Index stays mapped when redefined with complete descriptor, which differs only
+  by the [[Value]] field. Unmapped index is created.
+info: |
+  [[DefineOwnProperty]] ( P, Desc )
+
+  [...]
+  6. Let allowed be ? OrdinaryDefineOwnProperty(args, P, newArgDesc).
+  7. If allowed is false, return false.
+  8. If isMapped is true, then
+    [...]
+    b. Else,
+      i. If Desc.[[Value]] is present, then
+        1. Let setStatus be Set(map, P, Desc.[[Value]], false).
+        2. Assert: setStatus is true because formal parameters mapped by argument objects are always writable.
+  9. Return true.
+flags: [noStrict]
+---*/
+
+(function(a) {
+  Object.defineProperty(arguments, "0", {
+    value: "foo",
+    writable: true,
+    enumerable: true,
+    configurable: true,
+  });
+
+  assert.sameValue(a, "foo");
+  assert.sameValue(arguments[0], "foo");
+
+
+  Object.defineProperty(arguments, "1", {
+    value: "bar",
+    writable: true,
+    enumerable: true,
+    configurable: true,
+  });
+
+  assert.sameValue(arguments[1], "bar");
+})(0);