Codegen support for the argument definition test.

lib/compiler/implementation/resolver.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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
   DartType getType(TypeAnnotation annotation);
+  bool isParameterChecked(Element element);
 }
 
 class TreeElementMapping implements TreeElements {
-  Map<Node, Element> map;
-  Map<Node, Selector> selectors;
-  Map<TypeAnnotation, DartType> types;
+  final Map<Node, Element> map;
+  final Map<Node, Selector> selectors;
+  final Map<TypeAnnotation, DartType> types;
+  final Set<Element> checkedParameters;
 
   TreeElementMapping()
-    : map = new LinkedHashMap<Node, Element>(),
-      selectors = new LinkedHashMap<Node, Selector>(),
-      types = new LinkedHashMap<TypeAnnotation, DartType>();
+      : map = new LinkedHashMap<Node, Element>(),
+        selectors = new LinkedHashMap<Node, Selector>(),
+        types = new LinkedHashMap<TypeAnnotation, DartType>(),
+        checkedParameters = new Set<Element>();
 
   operator []=(Node node, Element element) => map[node] = element;
   operator [](Node node) => map[node];
   void remove(Node node) { map.remove(node); }
 
   void setType(TypeAnnotation annotation, DartType type) {
     types[annotation] = type;
   }
 
   DartType getType(TypeAnnotation annotation) => types[annotation];
 
   void setSelector(Node node, Selector selector) {
     selectors[node] = selector;
   }
 
   Selector getSelector(Node node) => selectors[node];
+
+  bool isParameterChecked(Element element) {
+    return checkedParameters.contains(element);
+  }
 }
 
 class ResolverTask extends CompilerTask {
   ResolverTask(Compiler compiler) : super(compiler);
 
   String get name => 'Resolver';
 
   TreeElements resolve(Element element) {
     return measure(() {
       ElementKind kind = element.kind;
@@ skipping 1294 matching lines @@
       String operatorString = node.selector.asOperator().source.stringValue;
       if (operatorString === 'is' || operatorString === 'as') {
         assert(node.arguments.tail.isEmpty());
         resolveTypeTest(node.arguments.head);
         resolvedArguments = true;
       } else if (operatorString === '?') {
         Element parameter = mapping[node.receiver];
         if (parameter === null || parameter.kind !== ElementKind.PARAMETER) {
           error(node.receiver, MessageKind.PARAMETER_NAME_EXPECTED);
         } else {
-          warning(node, MessageKind.GENERIC,
-                  ['argument definition test operator is not implemented.']);
+          mapping.checkedParameters.add(parameter);
         }
       }
     }
 
     if (!resolvedArguments) {
       resolveArguments(node.argumentsNode);
     }
 
     // If the selector is null, it means that we will not be generating
     // code for this as a send.
@@ skipping 1298 matching lines @@
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) {
     return library.find(name);
   }
 
   Element add(Element newElement) {
     throw "Cannot add an element in the top scope";
   }
   String toString() => '$element';
 }