Return null from stringValue and call slowToString() instead of toString().

dart/frog/leg/elements/elements.dart

 // Copyright (c) 2012, 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('elements');
 
 #import('../tree/tree.dart');
 #import('../scanner/scannerlib.dart');
 #import('../leg.dart');  // TODO(karlklose): we only need type.
 #import('../util/util.dart');
@@ skipping 519 matching lines @@
   void addMember(Element element, DiagnosticListener listener) {
     members = members.prepend(element);
     if (element.kind == ElementKind.GENERATIVE_CONSTRUCTOR ||
         element.modifiers.isFactory()) {
       constructors[element.name] = element;
     } else if (element.kind == ElementKind.GETTER
                || element.kind == ElementKind.SETTER) {
       Element existing = localMembers[element.name];
       if (existing != null) {
         if (existing.kind !== ElementKind.ABSTRACT_FIELD) {
-          listener.cancel('duplicate definition of $name', element: element);
+          listener.cancel('duplicate definition of ${name.slowToString()}',
+                          element: element);
           listener.cancel('existing definition', element: existing);
         } else {
           AbstractFieldElement field = existing;
           if (element.kind == ElementKind.GETTER) {
             if (field.getter != null) {
               listener.cancel('duplicate definition of getter ${element.name}',
                               element: element);
               listener.cancel('existing definition', element: field.getter);
             } else {
               field.getter = element;
@@ skipping 147 matching lines @@
     Element element = elements[send];
     // (o)() or foo()().
     if (element === null && send.selector.asIdentifier() === null) return true;
     if (element === null) return false;
     // foo() with foo a local or a parameter.
     return isLocal(element);
   }
 
   static SourceString constructConstructorName(SourceString receiver,
                                                SourceString selector) {
-    return new SourceString('$receiver\$$selector');
+    String r = receiver.slowToString();
+    String s = selector.slowToString();
+    return new SourceString('$r\$$s');
   }
 
   static SourceString constructOperatorName(SourceString receiver,
                                             SourceString selector,
                                             [bool isPrefix = false]) {
     String str = selector.stringValue;
     if (str === '==' || str === '!=') return Namer.OPERATOR_EQUALS;
 
     if (str === '~') str = 'not';
     else if (str === 'negate' || (str === '-' && isPrefix)) str = 'negate';
     else if (str === '[]') str = 'index';
     else if (str === '[]=') str = 'indexSet';
     else if (str === '*' || str === '*=') str = 'mul';
     else if (str === '/' || str === '/=') str = 'div';
     else if (str === '%' || str === '%=') str = 'mod';
     else if (str === '~/' || str === '~/=') str = 'tdiv';
     else if (str === '+' || str === '+=') str = 'add';
     else if (str === '-' || str === '-=') str = 'sub';
     else if (str === '<<' || str === '<<=') str = 'shl';
     else if (str === '>>' || str === '>>=') str = 'shr';
     else if (str === '>=') str = 'ge';
     else if (str === '>') str = 'gt';
     else if (str === '<=') str = 'le';
     else if (str === '<') str = 'lt';
     else if (str === '&' || str === '&=') str = 'and';
     else if (str === '^' || str === '^=') str = 'xor';
     else if (str === '|' || str === '|=') str = 'or';
+    else {
+      throw new Exception('Unhandled selector: ${selector.slowToString()}');
+    }
     return new SourceString('$receiver\$$str');
   }
 }
 
 // Represents a reference to a statement, either a label or the
 // default target of a break or continue.
 class StatementElement extends Element {
   final Statement origin;
   bool isBreakTarget = false;
   bool isContinueTarget = false;
 
   StatementElement(this.origin, Element enclosingElement)
       : super(const SourceString(""), ElementKind.STATEMENT, enclosingElement);
   StatementElement.label(String name, this.origin, Element enclosingElement)
       : super(new SourceString(name), ElementKind.STATEMENT, enclosingElement);
   bool get isTarget() => isBreakTarget || isContinueTarget;
 
   Node parseNode(DiagnosticListener l) => origin;
 }