Set the right context to resolve types of fields, closures and parameters.

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);
   Type getType(TypeAnnotation annotation);
 }
 
@@ skipping 559 matching lines @@
   ClassElement currentClass;
   bool typeRequired = false;
   StatementScope statementScope;
   int allowedCategory = ElementCategory.VARIABLE | ElementCategory.FUNCTION;
 
   ResolverVisitor(Compiler compiler, Element element)
     : this.mapping  = new TreeElementMapping(),
       this.enclosingElement = element,
       inInstanceContext = element.isInstanceMember()
           || element.isGenerativeConstructor(),
-      this.context  = element.isMember()
-        ? new ClassScope(element.enclosingElement, element.getLibrary())
-        : new TopScope(element.getLibrary()),
       this.currentClass = element.isMember() ? element.enclosingElement : null,
       this.statementScope = new StatementScope(),
-      super(compiler);
+      super(compiler) {
+    LibraryElement library = element.getLibrary();
+    element = element.getEnclosingMember();
+    if (element !== null) {
+      context = new ClassScope(element.enclosingElement, library);
+    } else {
+      this.context = new TopScope(library);
+    }
+  }
 
   Element lookup(Node node, SourceString name) {
     Element result = context.lookup(name);
     if (!inInstanceContext && result != null && result.isInstanceMember()) {
       error(node, MessageKind.NO_INSTANCE_AVAILABLE, [node]);
     }
     return result;
   }
 
   // Create, or reuse an already created, statement element for a statement.
@@ skipping 465 matching lines @@
     typeRequired = old;
     return result;
   }
 
   Element resolveTypeName(TypeAnnotation node) {
     Identifier typeName = node.typeName.asIdentifier();
     Send send = node.typeName.asSend();
     if (send !== null) {
       typeName = send.selector;
     }
-    if (typeName.source == Types.VOID) return compiler.types.voidType.element;
-    if (send !== null) {
+    if (typeName.source == Types.VOID) {
+      return compiler.types.voidType.element;
+    } else if (typeName.source.stringValue == Keyword.FACTORY.stringValue) {
+      return compiler.dynamicClass;

[ngeoffray, 2012/05/07 09:32:30]

You can remove this check, we have a fix:
https://chromiumcodereview.appspot.com/10332032

+    } else if (send !== null) {
       Element e = context.lookup(send.receiver.asIdentifier().source);
       if (e !== null && e.kind === ElementKind.PREFIX) {
         // The receiver is a prefix. Lookup in the imported members.
         PrefixElement prefix = e;
         return prefix.lookupLocalMember(typeName.source);
       } else if (e !== null && e.kind === ElementKind.CLASS) {
         // The receiver is the class part of a named constructor.
         return e;
       } else {
         return null;
@@ skipping 840 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";
   }
 }