Use ConstExp for storing constants.

pkg/docgen/test/multi_library_code/lib/test_lib.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 test_lib;
 
 import 'test_lib_foo.dart';
 import 'test_lib_bar.dart';
 export 'test_lib_foo.dart';
 export 'test_lib_bar.dart';
@@ skipping 22 matching lines @@
   void doThis(int A) {
     print(A);
   }
 }
 
 // A trivial use of `B` and `C` to eliminate import warnings
 B sampleMethod(C cInstance) {
   throw new UnimplementedError();
 }
 
-int positionalDefaultValues([int intConst = INT_CONST,
-    bool boolConst = BOOL_CONST, List listConst = LIST_CONST,
-    String stringConst = STRING_CONST, Map mapConst = MAP_CONST,
-    Map emptyMap = EMPTY_MAP_CONST]) {
+int positionalDefaultValues([
+    int intConst = 42,
+    bool boolConst = true,
+    List listConst = const [true, 42, 'Shanna', null, 3.14, const []],
+    String stringConst = 'Shanna',
+    Map mapConst = const {'a':1, 2: true, 'c': const [1,null,true]},
+    Map emptyMap = const {},
+    int referencedConst = INT_CONST,
+    ConstClass constructedConstant1 = const ConstClass<int>(0, true),
+    ConstClass constructedConstant2 = const ConstClass(1, false, str: "str")]) {
   throw new UnimplementedError();
 }
 
 const int INT_CONST = 42;
 
-const bool BOOL_CONST = true;
+class ConstClass<T> {
+  final bool boolField;
+  final int intField;
+  final String stringField;
 
-const LIST_CONST = const [true, 42, 'Shanna', null, 3.14, const []];
-
-const STRING_CONST = 'Shanna';
-
-const MAP_CONST = const {'a':1, 2: true, 'c': const [1,null,true]};
-
-const EMPTY_MAP_CONST = const {};
+  const ConstClass(this.intField, this.boolField, {String str: 'default'})
+      : this.stringField = str;
+}