Show import chains for unsupported dart:* library imports.

pkg/compiler/lib/src/apiimpl.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.
 
 library leg_apiimpl;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:package_config/packages.dart';
@@ skipping 173 matching lines @@
     result.add('Internal');
     return new Set<String>.from(result);
   }
 
   static bool hasOption(List<String> options, String option) {
     return options.indexOf(option) >= 0;
   }
 
   // TODO(johnniwinther): Merge better with [translateDartUri] when
   // [scanBuiltinLibrary] is removed.
-  String lookupLibraryPath(LibraryInfo info) {
+  String lookupLibraryPath(Uri uri, LibraryInfo info) {
     if (info == null) return null;
     if (!info.isDart2jsLibrary) return null;
-    if (!allowedLibraryCategories.contains(info.category)) return null;
+    if (!allowedLibraryCategories.contains(info.category)) {
+      registerDisallowedLibraryUse(uri);
+      return null;
+    }
     String path = info.dart2jsPath;
     if (path == null) {
       path = info.path;
     }
     return "lib/$path";
   }
 
   String lookupPatchPath(String dartLibraryName) {
     LibraryInfo info = lookupLibraryInfo(dartLibraryName);
     if (info == null) return null;
@@ skipping 101 matching lines @@
   Uri translateUri(Spannable node, Uri readableUri) {
     switch (readableUri.scheme) {
       case 'package': return translatePackageUri(node, readableUri);
       default: return readableUri;
     }
   }
 
   Uri translateDartUri(elements.LibraryElement importingLibrary,
                        Uri resolvedUri, tree.Node node) {
     LibraryInfo libraryInfo = lookupLibraryInfo(resolvedUri.path);
-    String path = lookupLibraryPath(libraryInfo);
+    String path = lookupLibraryPath(resolvedUri, libraryInfo);
     if (libraryInfo != null &&
         libraryInfo.category == "Internal") {
       bool allowInternalLibraryAccess = false;
       if (importingLibrary != null) {
         if (importingLibrary.isPlatformLibrary || importingLibrary.isPatch) {
           allowInternalLibraryAccess = true;
         } else if (importingLibrary.canonicalUri.path.contains(
                        'sdk/tests/compiler/dart2js_native')) {
           allowInternalLibraryAccess = true;
         }
       }
       if (!allowInternalLibraryAccess) {
         if (importingLibrary != null) {
           reportError(
               node,
               MessageKind.INTERNAL_LIBRARY_FROM,
               {'resolvedUri': resolvedUri,
                'importingUri': importingLibrary.canonicalUri});
         } else {
           reportError(
               node,
               MessageKind.INTERNAL_LIBRARY,
               {'resolvedUri': resolvedUri});
         }
       }
     }
     if (path == null) {
-      reportError(node, MessageKind.LIBRARY_NOT_FOUND,
-                  {'resolvedUri': resolvedUri});
+      if (libraryInfo == null) {
+        reportError(node, MessageKind.LIBRARY_NOT_FOUND,
+                    {'resolvedUri': resolvedUri});
+      } else {
+        reportError(node, MessageKind.LIBRARY_NOT_SUPPORTED,
+                    {'resolvedUri': resolvedUri});
+      }
+      // TODO(johnniwinther): Support signaling the error through the returned
+      // value.
       return null;
     }
     if (resolvedUri.path == 'html' ||
         resolvedUri.path == 'io') {
       // TODO(ahe): Get rid of mockableLibraryUsed when test.dart
       // supports this use case better.
       mockableLibraryUsed = true;
     }
     return libraryRoot.resolve(path);
   }
@@ skipping 155 matching lines @@
     print('$message: ${tryToString(exception)}');
     print(tryToString(stackTrace));
   }
 
   fromEnvironment(String name) => environment[name];
 
   LibraryInfo lookupLibraryInfo(String libraryName) {
     return library_info.LIBRARIES[libraryName];
   }
 }