Triage one co19 issue.

tests/co19/co19-analyzer.status

 # Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 [ $compiler == dartanalyzer ]
 # invalid argument for constant constructor
 Language/07_Classes/6_Constructors/3_Constant_Constructors_A05_t02: fail
 
 # TBD: should we check that argument for dynamic parameter of constant constructor is not compatible with operation that is performed with it?
 Language/12_Expressions/01_Constants_A16_t03: fail
 
 # TBD: should we report _error_ when constant creation uses arguments with types incompatible with parameters?
 Language/12_Expressions/12_Instance_Creation/2_Const_A09_t02: fail
 Language/12_Expressions/12_Instance_Creation/2_Const_A09_t03: fail
 
 # TBF: infinite look: class A {const A();final m = const A();}
 Language/12_Expressions/01_Constants_A17_t03: fail
 
 # analyzer issue https://code.google.com/p/dart/issues/detail?id=11534
 Language/15_Types/4_Interface_Types_A11_t01: Skip
 Language/15_Types/4_Interface_Types_A11_t02: Skip
 
-# TBF: Hence, a static warning will not be issued if f has no declared return type, since the return type would be dynamic and dynamic may be assigned to void.
-Language/13_Statements/11_Return_A07_t01: fail
-
 
 LibTest/core/Uri/decodeQueryComponent_A02_t01: fail # co19 Issue 591
 
 # co19 issue #380, Strings class has been removed
 LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A04_t01: fail, OK
 
 # co19 issue #400, collection library reorg
 LibTest/core/String/concat_A01_t01: fail, OK
 LibTest/core/String/concat_A02_t01: fail, OK
 LibTest/core/Set/isSubsetOf_A01_t01: fail, OK
@@ skipping 61 matching lines @@
 Language/14_Libraries_and_Scripts/5_URIs_A01_t24: fail, OK
 Language/14_Libraries_and_Scripts/5_URIs_A01_t25: fail, OK
 
 # co19 issue #596: initializing final variable at declaration and in constructor
 Language/07_Classes/6_Constructors/1_Generative_Constructors_A12_t02: fail, OK
 Language/07_Classes/6_Constructors/1_Generative_Constructors_A20_t02: fail, OK
 
 # co19 issue #597: concrete class with abstract method
 Language/07_Classes/4_Abstract_Instance_Members_A07_t08: fail, OK
 
+# co19 issue #609, return type of "factory M" is M, so we need static warning for "return;".
+Language/13_Statements/11_Return_A07_t01: fail, OK