Partial fix for Angular Annotations viewed in Docgen.

pkg/docgen/lib/src/models/annotation.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 docgen.models.annotation;
 
 import '../exports/mirrors_util.dart' as dart2js_util;
 import '../exports/source_mirrors.dart';
 
 import '../library_helpers.dart';
 
 import 'library.dart';
 import 'mirror_based.dart';
 
 /// Holds the name of the annotation, and its parameters.
 class Annotation extends MirrorBased {
   /// The class of this annotation.
   final ClassMirror mirror;
   final Library owningLibrary;
   List<String> parameters;
 
   Annotation(InstanceMirror originalMirror, this.owningLibrary)
       : mirror = originalMirror.type {
-    parameters = dart2js_util.variablesOf(originalMirror.type.declarations)
-        .where((e) => e.isFinal)
+    var curMirror = originalMirror.type;
+    Map<Symbol, DeclarationMirror> allDeclarations =
+        new Map.from(curMirror.declarations);
+    // This method assumes that our users aren't creating deep inheritance
+    // chains of custom annotation inheritance. If this is not the case,
+    // re-write this section for performance.
+    while (curMirror.superclass !=  null &&
+        curMirror.superclass.simpleName.toString() != 'Object') {
+      allDeclarations.addAll(curMirror.superclass.declarations);
+      curMirror = curMirror.superclass;
+    }
+
+    // TODO(efortuna): Some originalMirrors, such as the
+    // Dart2JsMapConstantMirror and Dart2JsListConstantMirror don't have a
+    // reflectee field, but we want the value of the parameter from them.
+    // Gross workaround is to assemble the object manually.
+    // See issue 18346.
+    parameters = dart2js_util.variablesOf(allDeclarations)
+        .where((e) => e.isFinal &&
+            originalMirror.getField(e.simpleName).hasReflectee)
         .map((e) => originalMirror.getField(e.simpleName).reflectee)
         .where((e) => e != null)
         .toList();
   }
 
   Map toMap() => {
     'name': getDocgenObject(mirror, owningLibrary).docName,
     'parameters': parameters
   };
 }