Handle exports being registered before declarations.

sdk/lib/_internal/compiler/implementation/library_loader.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.
 
 part of dart2js;
 
 /**
  * [CompilerTask] for loading libraries and setting up the import/export scopes.
  *
  * The library loader uses four different kinds of URIs in different parts of
@@ skipping 696 matching lines @@
     pendingExportMap.clear();
     return pendingExports;
   }
 
   /**
    * Adds [element] to the export scope for this node. If the [element] name
    * is a duplicate, an error element is inserted into the export scope.
    */
   Element addElementToExportScope(Compiler compiler, Element element,
                                   Link<Export> exports) {
-
     SourceString name = element.name;
 
     void reportDuplicateExport(Element duplicate,
                                Link<Export> duplicateExports,
                                {bool reportError: true}) {
+      assert(invariant(library, !duplicateExports.isEmpty,
+          message: "No export for $duplicate from ${duplicate.getLibrary()} "
+                   "in $library."));
       compiler.withCurrentElement(library, () {
         for (Export export in duplicateExports) {
           if (reportError) {
             compiler.reportError(export,
                 MessageKind.DUPLICATE_EXPORT, {'name': name});
             reportError = false;
           } else {
             compiler.reportInfo(export,
                 MessageKind.DUPLICATE_EXPORT_CONT, {'name': name});
           }
         }
       });
     }
 
     void reportDuplicateExportDecl(Element duplicate,
                                    Link<Export> duplicateExports) {
+      assert(invariant(library, !duplicateExports.isEmpty,
+          message: "No export for $duplicate from ${duplicate.getLibrary()} "
+                   "in $library."));
       compiler.reportInfo(duplicate, MessageKind.DUPLICATE_EXPORT_DECL,
           {'name': name, 'uriString': duplicateExports.head.uri});
     }
 
     Element existingElement = exportScope[name];
     if (existingElement != null && existingElement != element) {
       if (existingElement.isErroneous()) {
         reportDuplicateExport(element, exports);
         reportDuplicateExportDecl(element, exports);
         element = existingElement;
-      } else if (existingElement.getLibrary() != library) {
+      } else if (existingElement.getLibrary() == library) {
+        // Do nothing. [existingElement] hides [element].
+      } else if (element.getLibrary() == library) {
+        // Do nothing. [element] hides [existingElement].

[karlklose, 2013/10/03 13:35:19]

Remove "Do nothing."

[Johnni Winther, 2013/10/03 13:38:51]

Done.

+        exportScope[name] = element;
+        exporters[element] = exports;
+      } else {
         // Declared elements hide exported elements.
         Link<Export> existingExports = exporters[existingElement];
         reportDuplicateExport(existingElement, existingExports);
         reportDuplicateExport(element, exports, reportError: false);
         reportDuplicateExportDecl(existingElement, existingExports);
         reportDuplicateExportDecl(element, exports);
         element = exportScope[name] = new ErroneousElementX(
             MessageKind.DUPLICATE_EXPORT, {'name': name}, name, library);
       }
     } else {
@@ skipping 145 matching lines @@
   }
 
   /**
    * Registers all top-level entities of [library] as starting point for the
    * fixed-point computation of the import/export scopes.
    */
   void registerLibraryExports(LibraryElement library) {
     nodeMap[library].registerInitialExports();
   }
 }