Fix for JavaFile path in DDA.

pkg/analyzer/lib/src/analyzer_impl.dart

 // Copyright (c) 2013, 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_impl;
 
 import 'dart:io';
 
+import 'package:path/path.dart' as pathos;
+
 import 'generated/java_io.dart';
 import 'generated/engine.dart';
 import 'generated/error.dart';
 import 'generated/source_io.dart';
 import 'generated/sdk.dart';
 import 'generated/sdk_io.dart';
 import 'generated/ast.dart';
 import 'generated/element.dart';
 import '../options.dart';
 
@@ skipping 102 matching lines @@
       Set<CompilationUnitElement> units) {
     if (unit == null || units.contains(unit)) {
       return;
     }
     units.add(unit);
     sources.add(unit.source);
   }
 
   void addLibrarySources(LibraryElement library, Set<LibraryElement> libraries,
       Set<CompilationUnitElement> units) {
-    if (library == null || libraries.contains(library)) {
+    if (library == null || !libraries.add(library) ) {
       return;
     }
-    libraries.add(library);
     // may be skip library
     {
       UriKind uriKind = library.source.uriKind;
       // Optionally skip package: libraries.
       if (!options.showPackageWarnings && uriKind == UriKind.PACKAGE_URI) {
         return;
       }
       // Optionally skip SDK libraries.
       if (!options.showSdkWarnings && uriKind == UriKind.DART_URI) {
         return;
@@ skipping 40 matching lines @@
 
   /**
    * Returns the [UriKind] for the given input file. Usually {@link UriKind#FILE_URI}, but if
    * the given file is located in the "lib" directory of the [sdk], then returns
    * {@link UriKind#DART_URI}.
    */
   static UriKind getUriKind(JavaFile file) {
     // may be file in SDK
     if (sdk is DirectoryBasedDartSdk) {
       DirectoryBasedDartSdk directoryBasedSdk = sdk;
-      String sdkLibPath = directoryBasedSdk.libraryDirectory.getPath() + JavaFile.separator;
-      if (file.getPath().startsWith(sdkLibPath)) {
-        return UriKind.DART_URI;
+      var libraryDirectory = directoryBasedSdk.libraryDirectory.getAbsolutePath();
+      var sdkLibPath = libraryDirectory + pathos.separator;
+      var filePath = file.getPath();
+      if (filePath.startsWith(sdkLibPath)) {
+        var internalPath = pathos.join(libraryDirectory, '_internal') + pathos.separator;
+        if (!filePath.startsWith(internalPath)) {
+          return UriKind.DART_URI;
+        }
       }
     }
     // some generic file
     return UriKind.FILE_URI;
   }
 }