Disallow generator declarations in certain locations

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index c36a9645db9fc57299490cee8b2273a1434770dd..fbd9915ed19932219e81677eaf68c3844ea3c052 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -7142,6 +7142,13 @@ TEST(FunctionDeclarationError) {
     "with ({}) label: function f() { };",
     "if (true) label: function f() {}",
     "if (true) {} else label: function f() {}",
+    "if (true) function* f() { }",
+    "label: function* f() { }",
+    // TODO(littledan, v8:4806): Ban duplicate generator declarations in
+    // a block, maybe by tracking whether a Variable is a generator declaration
+    // "{ function* f() {} function* f() {} }",
+    // "{ function f() {} function* f() {} }",
+    // "{ function* f() {} function f() {} }",
     NULL
   };
   // Valid only in sloppy mode, with or without