diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_6/Generators/syntax.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_6/Generators/syntax.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,97 @@
+// This file was written by Andy Wingo <wingo@igalia.com> and originally
+// contributed to V8 as generators-parsing.js, available here:
+//
+// http://code.google.com/p/v8/source/browse/branches/bleeding_edge/test/mjsunit/harmony/generators-parsing.js
+
+function assertSyntaxError(str) {
+    var msg;
+    var evil = eval;
+    try {
+        // Non-direct eval.
+        evil(str);
+    } catch (exc) {
+        if (exc instanceof SyntaxError)
+            return;
+        msg = "Assertion failed: expected SyntaxError, got " + exc;
+    }
+    if (msg === undefined)
+        msg = "Assertion failed: expected SyntaxError, but no exception thrown";
+    throw new Error(msg + " - " + str);
+}
+
+// Yield statements.
+function* g() { yield 3; yield 4; }
+
+// Yield expressions.
+function* g() { (yield 3) + (yield 4); }
+
+// You can have a generator in strict mode.
+function* g() { "use strict"; yield 3; yield 4; }
+
+// Generators can have return statements also, which internally parse to a kind
+// of yield expression.
+function* g() { yield 1; return; }
+function* g() { yield 1; return 2; }
+function* g() { yield 1; return 2; yield "dead"; }
+
+// Generator expression.
+(function* () { yield 3; });
+
+// Named generator expression.
+(function* g() { yield 3; });
+
+// Generators do not have to contain yield expressions.
+function* g() { }
+
+// YieldExpressions can occur in the RHS of a YieldExpression.
+function* g() { yield yield 1; }
+function* g() { yield 3 + (yield 4); }
+
+// Generator definitions with a name of "yield" are not specifically ruled out
+// by the spec, as the `yield' name is outside the generator itself.  However,
+// in strict-mode, "yield" is an invalid identifier.
+function* yield() { (yield 3) + (yield 4); }
+assertSyntaxError("function* yield() { 'use strict'; (yield 3) + (yield 4); }");
+
+// In classic mode, yield is a normal identifier, outside of generators.
+function yield(yield) { yield: yield (yield + yield (0)); }
+
+// Yield is always valid as a key in an object literal.
+({ yield: 1 });
+function* g() { yield ({ yield: 1 }) }
+function* g() { yield ({ get yield() { return 1; }}) }
+
+// Yield is a valid property name.
+function* g(obj) { yield obj.yield; }
+
+// Checks that yield is a valid label in classic mode, but not valid in a strict
+// mode or in generators.
+function f() { yield: 1 }
+assertSyntaxError("function f() { 'use strict'; yield: 1 }")
+assertSyntaxError("function* g() { yield: 1 }")
+
+// Yield is only a keyword in the body of the generator, not in nested
+// functions.
+function* g() { function f(yield) { yield (yield + yield (0)); } }
+
+// Yield needs a RHS.
+assertSyntaxError("function* g() { yield; }");
+
+// Yield in a generator is not an identifier.
+assertSyntaxError("function* g() { yield = 10; }");
+
+// Yield binds very loosely, so this parses as "yield (3 + yield 4)", which is
+// invalid.
+assertSyntaxError("function* g() { yield 3 + yield 4; }");
+
+// Yield is still a future-reserved-word in strict mode
+assertSyntaxError("function f() { 'use strict'; var yield = 13; }");
+
+// The name of the NFE is let-bound in G, so is invalid.
+assertSyntaxError("function* g() { yield (function yield() {}); }");
+
+// In generators, yield is invalid as a formal argument name.
+assertSyntaxError("function* g(yield) { yield (10); }");
+
+if (typeof reportCompare == "function")
+    reportCompare(true, true);