Fix a spurious warning in Frog selfhost

frog/member.dart

 // Copyright (c) 2011, 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.
 
 /** A formal parameter to a [Method]. */
 class Parameter {
   FormalNode definition;
 
   String name;
   Type type;
@@ skipping 1451 matching lines @@
       return members[0].invoke(context, node, target, args, isDynamic);
     }
     final targets = members.filter((m) => m.canInvoke(context, args));
     if (targets.length == 1) {
       return targets[0].invoke(context, node, target, args, isDynamic);
     }
 
     Value returnValue = null;
     for (var member in targets) {
       final res = member.invoke(context, node, target, args, isDynamic:true);
+      // TODO(jmesserly): If the code has different type checks, it will fail to
+      // unify and go through a dynamic stub. Good so far. However, we'll end
+      // up with a bogus unused temp generated (usually "var $0"). We need a way
+      // to throw away temps when we throw away the code.
       returnValue = _tryUnion(returnValue, res, node);
     }
 
     if (returnValue == null) {
       return _makeError(node, target, 'method');
     }
 
     if (returnValue.code == null) {
       // TODO(jmesserly): make operators less special.
       if (isOperator) {
@@ skipping 133 matching lines @@
   }
 
   void forEach(void f(Member member)) {
     factories.forEach((_, Map constructors) {
       constructors.forEach((_, Member member) {
         f(member);
       });
     });
   }
 }