Use declared variables to select the correct configuration for resolution

pkg/analyzer/lib/src/dart/element/builder.dart

 // Copyright (c) 2014, 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 analyzer.src.dart.element.builder;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 151 matching lines @@
     //
     libraryElement.imports = imports;
     libraryElement.exports = exports;
     return null;
   }
 
   @override
   Object visitExportDirective(ExportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     node.element = null;
-    Source exportedSource = node.source;
+    Source exportedSource = node.selectedSource;
     int exportedTime = sourceModificationTimeMap[exportedSource] ?? -1;
     // The exported source will be null if the URI in the export
     // directive was invalid.
     LibraryElement exportedLibrary = exportLibraryMap[exportedSource];
     if (exportedLibrary != null) {
       ExportElementImpl exportElement = new ExportElementImpl(node.offset);
       exportElement.metadata = _getElementAnnotations(node.metadata);
       StringLiteral uriLiteral = node.uri;
       if (uriLiteral != null) {
         exportElement.uriOffset = uriLiteral.offset;
@@ skipping 21 matching lines @@
             [uriLiteral.toSource()]));
       }
     }
     return null;
   }
 
   @override
   Object visitImportDirective(ImportDirective node) {
     // Remove previous element. (It will remain null if the target is missing.)
     node.element = null;
-    Source importedSource = node.source;
+    Source importedSource = node.selectedSource;
     int importedTime = sourceModificationTimeMap[importedSource] ?? -1;
     // The imported source will be null if the URI in the import
     // directive was invalid.
     LibraryElement importedLibrary = importLibraryMap[importedSource];
     if (importedLibrary != null) {
       if (importedLibrary.isDartCore) {
         explicitlyImportsCore = true;
       }
       ImportElementImpl importElement = new ImportElementImpl(node.offset);
       importElement.metadata = _getElementAnnotations(node.metadata);
@@ skipping 1231 matching lines @@
     return null;
   }
 
   /**
    * Return the lexical identifiers associated with the given [identifiers].
    */
   static List<String> _getIdentifiers(NodeList<SimpleIdentifier> identifiers) {
     return identifiers.map((identifier) => identifier.name).toList();
   }
 }