Implement 'assignToRef' resynthesizing.

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 441 matching lines @@
         case UnlinkedConstOperation.assignToRef:
         case UnlinkedConstOperation.assignToProperty:
         case UnlinkedConstOperation.assignToIndex:
         case UnlinkedConstOperation.extractIndex:
         case UnlinkedConstOperation.invokeMethod:
         case UnlinkedConstOperation.cascadeSectionBegin:
         case UnlinkedConstOperation.cascadeSectionEnd:
         case UnlinkedConstOperation.typeCast:
         case UnlinkedConstOperation.typeCheck:
         case UnlinkedConstOperation.throwException:
-          throw new UnimplementedError('$operation');
+          _push(AstFactory.identifier3(r'$notConst$'));

[Paul Berry, 2016/05/03 19:33:41]

This seems dangerous to me, since it breaks the tracking of intPtr.  Which means
that later in the loop, we might get garbage data in our intPtr, leading to a
crash.

Since it just takes one invalid operation to render the entire constant
expression invalid, how about if we just do this instead?

return AstFactory.identifier3(r'$notConst$');

[scheglov, 2016/05/03 20:02:44]

Done.

+          break;
       }
     }
     return stack.single;
   }
 
   List<Expression> _buildArguments() {
     List<Expression> arguments;
     {
       int numNamedArgs = uc.ints[intPtr++];
       int numPositionalArgs = uc.ints[intPtr++];
@@ skipping 2173 matching lines @@
   static String _getElementIdentifier(String name, ReferenceKind kind) {
     if (kind == ReferenceKind.topLevelPropertyAccessor ||
         kind == ReferenceKind.propertyAccessor) {
       if (!name.endsWith('=')) {
         return name + '?';
       }
     }
     return name;
   }
 }