Handle setter without getter for compounds in SemanticSendVisitor

tests/compiler/dart2js/semantic_visitor_test.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.semantics_visitor_test;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/constants/expressions.dart';
@@ skipping 2057 matching lines @@
           set a(_) {}
         }
 
         class C extends B {
           m() => super.a++;
         }
         ''',
         const Visit(VisitKind.VISIT_SUPER_FIELD_SETTER_POSTFIX,
             getter: 'field(A#a)', setter: 'setter(B#a)',
             operator: '++')),
+
+    const Test(
+        '''
+        set topLevel(var value) { }
+        m() => topLevel++;
+        ''',
+        const Visit(VisitKind.ERROR_UNRESOLVED_POSTFIX,
+            operator: '++')),
   ],
   'Constructor invocations': const [
     const Test(
         '''
         class Class {
           const Class(a, b);
         }
         m() => const Class(true, 42);
         ''',
         const Visit(VisitKind.VISIT_CONST_CONSTRUCTOR_INVOKE,
@@ skipping 2022 matching lines @@
       arg) {
     // TODO: implement errorUnresolvedInvoke
   }
 
   @override
   errorUnresolvedPostfix(
       Send node,
       ErroneousElement element,
       IncDecOperator operator,
       arg) {
-    // TODO: implement errorUnresolvedPostfix
+    visits.add(new Visit(
+        VisitKind.ERROR_UNRESOLVED_POSTFIX, operator: operator));
   }
 
   @override
   errorUnresolvedPrefix(
       Send node,
       ErroneousElement element,
       IncDecOperator operator,
       arg) {
     // TODO: implement errorUnresolvedPrefix
   }
@@ skipping 456 matching lines @@
   VISIT_GENERATIVE_CONSTRUCTOR_INVOKE,
   VISIT_REDIRECTING_GENERATIVE_CONSTRUCTOR_INVOKE,
   VISIT_FACTORY_CONSTRUCTOR_INVOKE,
   VISIT_REDIRECTING_FACTORY_CONSTRUCTOR_INVOKE,
 
   ERROR_UNRESOLVED_CLASS_CONSTRUCTOR_INVOKE,
   ERROR_UNRESOLVED_CONSTRUCTOR_INVOKE,
   ERROR_ABSTRACT_CLASS_CONSTRUCTOR_INVOKE,
   ERROR_UNRESOLVED_REDIRECTING_FACTORY_CONSTRUCTOR_INVOKE,
 
-  // TODO(johnniwinther): Add tests for error cases.
+  ERROR_UNRESOLVED_POSTFIX,
+
+  // TODO(johnniwinther): Add tests for more error cases.
 }