diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/function-tosource-constructor.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/function-tosource-constructor.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,18 @@
+var f = Function("a", "b", "return a + b;");
+assertEq(f.toString(), "function anonymous(a, b) {\nreturn a + b;\n}");
+assertEq(f.toSource(), "(function anonymous(a, b) {\nreturn a + b;\n})");
+assertEq(decompileFunction(f), f.toString());
+assertEq(decompileBody(f), "return a + b;");
+f = Function("a", "...rest", "return rest[42] + b;");
+assertEq(f.toString(), "function anonymous(a, ...rest) {\nreturn rest[42] + b;\n}");
+assertEq(f.toSource(), "(function anonymous(a, ...rest) {\nreturn rest[42] + b;\n})")
+assertEq(decompileFunction(f), f.toString());
+assertEq(decompileBody(f), "return rest[42] + b;");
+f = Function("x", "return let (y) x;");
+assertEq(f.toSource(), "(function anonymous(x) {\nreturn let (y) x;\n})");
+f = Function("");
+assertEq(f.toString(), "function anonymous() {\n\n}");
+f = Function("", "(abc)");
+assertEq(f.toString(), "function anonymous() {\n(abc)\n}");
+f = Function("", "return function (a, b) a + b;")();
+assertEq(f.toString(), "function (a, b) a + b");