Use isValidConst flag to distinguish between const / final expressions.

pkg/analyzer/lib/src/summary/resynthesize.dart

 // Copyright (c) 2015, 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 summary_resynthesizer;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 268 matching lines @@
   int doublePtr = 0;
   int stringPtr = 0;
   int refPtr = 0;
   final List<Expression> stack = <Expression>[];
 
   _ConstExprBuilder(this.resynthesizer, this.uc);
 
   Expression get expr => stack.single;
 
   Expression build() {
-    if (uc.isInvalid) {
+    if (!uc.isValidConst) {
       return AstFactory.identifier3(r'$$invalidConstExpr$$');
     }
     for (UnlinkedConstOperation operation in uc.operations) {
       switch (operation) {
         case UnlinkedConstOperation.pushNull:
           _push(AstFactory.nullLiteral());
           break;
         // bool
         case UnlinkedConstOperation.pushFalse:
           _push(AstFactory.booleanLiteral(false));
@@ skipping 2339 matching lines @@
   static String _getElementIdentifier(String name, ReferenceKind kind) {
     if (kind == ReferenceKind.topLevelPropertyAccessor ||
         kind == ReferenceKind.propertyAccessor) {
       if (!name.endsWith('=')) {
         return name + '?';
       }
     }
     return name;
   }
 }