Implement the function.sent proposal.

test/mjsunit/harmony/function-sent.js

+// Copyright 2016 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.
+
+// Flags: --harmony-function-sent
+
+
+{
+  function* g() { return function.sent }
+  assertEquals({value: 42, done: true}, g().next(42));
+}
+
+
+{
+  function* g() {
+    try {
+      yield function.sent;
+    } finally {
+      yield function.sent;
+      return function.sent;
+    }
+  }
+
+  {
+    x = g();
+    assertEquals({value: 1, done: false}, x.next(1));
+    assertEquals({value: 2, done: false}, x.next(2));
+    assertEquals({value: 3, done: true}, x.next(3));
+  }
+
+  {
+    x = g();
+    assertEquals({value: 1, done: false}, x.next(1));
+    assertEquals({value: 2, done: false}, x.throw(2));
+    assertEquals({value: 3, done: true}, x.next(3));
+  }
+}
+
+
+{
+  function* inner() {
+    try {
+      yield function.sent;
+    } finally {
+      return 666;
+    }
+  }
+
+  function* g() {
+    yield function.sent;
+    yield* inner();
+    return function.sent;
+  }
+
+  {
+    x = g();
+    assertEquals({value: 1, done: false}, x.next(1));
+    assertEquals({value: undefined, done: false}, x.next(2));
+    assertEquals({value: 3, done: true}, x.next(3));
+  }
+
+  {
+    x = g();
+    assertEquals({value: 1, done: false}, x.next(1));
+    assertEquals({value: undefined, done: false}, x.next(2));
+    assertEquals({value: 42, done: true}, x.throw(42));
+  }
+}
+
+
+assertThrows("function f() { return function.sent }", SyntaxError);
+assertThrows("() => { return function.sent }", SyntaxError);
+assertThrows("() => { function.sent }", SyntaxError);
+assertThrows("() => function.sent", SyntaxError);
+assertThrows("({*f() { function.sent }})", SyntaxError);
+assertDoesNotThrow("({*f() { return function.sent }})");