[decorators] Add flag, accessor keyword and token

This change doesn't do any functionality changes.

Bug: 42202709
Change-Id: I613b96b6e7630e10748e31162080a61e7da4c2a1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/5542951
Commit-Queue: Luis Pardo <lpardosixtos@microsoft.com>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#94086}

test/staging/decorators/accessor-as-identifier.js

@@ -0,0 +1,205 @@
+// Copyright 2024 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/*---
+description: Test `accessor` can be used as an identifier.
+features: [decorators]
+---*/
+
+(function TestAccessorIdentifierDeclaration() {
+  var accessor;
+  var foo, accessor;
+  try {
+  } catch (accessor) {
+  }
+  function accessor() {}
+  (function accessor() {})
+  function foo(accessor) {}
+  function foo(bar, accessor) {}
+  accessor = 1;
+  accessor += 1;
+  var foo = accessor = 1;
+  ++accessor;
+  accessor++;
+})();
+
+(function TestAccessorIdentifierLetDeclaration() {
+  let accessor;
+  for (let accessor; false;) {
+  }
+  for (let accessor in {}) {
+  }
+  for (let accessor of []) {
+  }
+})();
+
+(function TestAccessorIdentifierConstDeclaration() {
+  const accessor = null;
+  for (const accessor = null; false;) {
+  }
+  for (const accessor in {}) {
+  }
+  for (const accessor of []) {
+  }
+})();
+
+(function TestAccessorAsClassElementName() {
+  let C = class {
+    accessor;
+  }
+  let c = new C();
+  assert.sameValue(c.accessor, undefined);
+
+  C = class {
+    accessor = 42;
+  }
+  c = new C();
+  assert.sameValue(c.accessor, 42);
+
+  C = class {
+    // Intentional new line after "accessor".
+    accessor
+    a = 42;
+  }
+  c = new C();
+  assert.sameValue(c.a, 42);
+  assert.sameValue(c.accessor, undefined);
+
+  C = class {
+    accessor() {
+      return 42;
+    }
+  }
+  c = new C();
+  assert.sameValue(c.accessor(), 42);
+
+  C = class {
+    #value = 42;
+    get accessor() {
+      return this.#value;
+    };
+    set accessor(value) {
+      this.#value = value
+    }
+  }
+  c = new C();
+  assert.sameValue(c.accessor, 42);
+  c.accessor = 43;
+  assert.sameValue(c.accessor, 43);
+})();
+
+(function TestAccessorAsStaticClassElementName() {
+  class C1 {
+    static accessor;
+  }
+  assert.sameValue(C1.accessor, undefined);
+
+  class C2 {
+    static accessor = 42;
+  }
+  assert.sameValue(C2.accessor, 42);
+
+  class C3 {
+    // Intentional new line after "accessor".
+    static accessor
+    static a = 42;
+  }
+  assert.sameValue(C3.a, 42);
+  assert.sameValue(C3.accessor, undefined);
+
+  class C4{
+    static accessor() {
+      return 42;
+    }
+  }
+  assert.sameValue(C4.accessor(), 42);
+
+  class C5 {
+    static #value = 42;
+    static get accessor() {
+      return C5.#value;
+    };
+    static set accessor(value) {
+      this.#value = value
+    }
+  }
+  assert.sameValue(C5.accessor, 42);
+  C5.accessor = 43;
+  assert.sameValue(C5.accessor, 43);
+})();
+
+(function TestAccessorAsPrivateClassElementName() {
+  let C = class {
+    #accessor = 42;
+    test() {
+      assert.sameValue(this.#accessor, 42);
+    }
+  }
+  let c = new C();
+  c.test();
+
+  C = class {
+    #accessor() {
+      return 42;
+    }
+    test() {
+      assert.sameValue(this.#accessor(), 42);
+    }
+  }
+  c = new C();
+  c.test();
+
+  C = class {
+    #value = 42;
+    get #accessor() {
+      return this.#value
+    };
+    set #accessor(value) {
+      this.#value = value
+    }
+    test() {
+      assert.sameValue(this.#accessor, 42);
+      this.#accessor = 43;
+      assert.sameValue(this.#accessor, 43);
+    }
+  }
+  c = new C();
+  c.test();
+})();
+
+(function TestAccessorAsStaticPrivateClassElementName() {
+  class C1 {
+    static #accessor = 42;
+    static test() {
+      assert.sameValue(C1.#accessor, 42);
+    }
+  }
+  C1.test();
+
+  class C2 {
+    static #accessor() {
+      return 42;
+    }
+    static test() {
+      assert.sameValue(C2.#accessor(), 42);
+    }
+  }
+  C2.test();
+
+  class C3 {
+    static #value = 42;
+    static get #accessor() {
+      return C3.#value
+    };
+    static set #accessor(value) {
+      C3.#value = value
+    }
+    static test() {
+      assert.sameValue(C3.#accessor, 42);
+      C3.#accessor = 43;
+      assert.sameValue(C3.#accessor, 43);
+    }
+  }
+  C3.test();
+})();