Handle setter without getter for compounds in SemanticSendVisitor

pkg/compiler/lib/src/resolution/access_semantics.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.
 
 // TODO(johnniwinther): Temporarily copied from analyzer2dart. Merge when
 // we shared code with the analyzer and this semantic visitor is complete.
 
 /**
  * Code for classifying the semantics of identifiers appearing in a Dart file.
  */
@@ skipping 289 matching lines @@
   final CompoundAccessKind compoundAccessKind;
   final Element getter;
   final Element setter;
 
   CompoundAccessSemantics(this.compoundAccessKind,
                           this.getter,
                           this.setter)
       : super._(AccessKind.COMPOUND);
 
   Element get element => setter;
+
+  String toString() {
+    StringBuffer sb = new StringBuffer();
+    sb.write('CompoundAccessSemantics[');
+    sb.write('kind=$compoundAccessKind');
+    if (getter != null) {
+      sb.write(',getter=');
+      sb.write('${getter}');
+    }
+    if (setter != null) {
+      sb.write(',setter=');
+      sb.write('${setter}');
+    }
+    sb.write(']');
+    return sb.toString();
+  }
 }
 
 /// Enum representing the different kinds of destinations which a constructor
 /// invocation might refer to.
 enum ConstructorAccessKind {
   /// An invocation of a generative constructor.
   ///
   /// For instance
   ///     class C {
   ///       C();
@@ skipping 102 matching lines @@
 
   RedirectingFactoryConstructorAccessSemantics(
       ConstructorAccessKind kind,
       Element element,
       DartType type,
       this.effectiveTargetSemantics)
       : super(kind, element, type);
 }