[es6] Fix parsing of 'yield' in function and generator expressions

test/mjsunit/es6/generators-parsing.js

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 106 matching lines @@
 // Yield in a generator is not an identifier.
 assertThrows("function* g() { yield = 10; }", SyntaxError);
 
 // Yield binds very loosely, so this parses as "yield (3 + yield 4)", which is
 // invalid.
 assertThrows("function* g() { yield 3 + yield 4; }", SyntaxError);
 
 // Yield is still a future-reserved-word in strict mode
 assertThrows("function f() { \"use strict\"; var yield = 13; }", SyntaxError);
 
-// The name of the NFE is let-bound in G, so is invalid.
-assertThrows("function* g() { yield (function yield() {}); }", SyntaxError);
+// The name of the NFE is bound in the generator expression, so is invalid.
+assertThrows("function f() { (function* yield() {}); }", SyntaxError);
 
 // In generators, yield is invalid as a formal argument name.
 assertThrows("function* g(yield) { yield (10); }", SyntaxError);