Don't resynthesize invalid constant expressions at all.

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/standard_ast_factory.dart';
@@ skipping 312 matching lines @@
       if (e is ConstructorElement) {
         return e;
       }
     }
     throw new StateError(
         'Unable to find the enclosing constructor of $context');
   }
 
   Expression build() {
     if (!uc.isValidConst) {
-      return AstTestFactory.identifier3(r'$$invalidConstExpr$$');
+      return null;
     }
     for (UnlinkedExprOperation operation in uc.operations) {
       switch (operation) {
         case UnlinkedExprOperation.pushNull:
           _push(AstTestFactory.nullLiteral());
           break;
         // bool
         case UnlinkedExprOperation.pushFalse:
           _push(AstTestFactory.booleanLiteral(false));
           break;
@@ skipping 1221 matching lines @@
       libraryResynthesizer.summaryResynthesizer;
 
   TypeProvider get typeProvider => summaryResynthesizer.typeProvider;
 
   /**
    * Build [ElementAnnotationImpl] for the given [UnlinkedExpr].
    */
   ElementAnnotationImpl buildAnnotation(ElementImpl context, UnlinkedExpr uc) {
     ElementAnnotationImpl elementAnnotation = new ElementAnnotationImpl(unit);
     Expression constExpr = _buildConstExpression(context, uc);
-    if (constExpr is Identifier) {
+    if (constExpr == null) {
+      // Invalid constant expression.
+    } else if (constExpr is Identifier) {
       ArgumentList arguments =
           constExpr.getProperty(_ConstExprBuilder.ARGUMENT_LIST);
       elementAnnotation.element = constExpr.staticElement;
       elementAnnotation.annotationAst =
           AstTestFactory.annotation2(constExpr, null, arguments);
     } else if (constExpr is InstanceCreationExpression) {
       elementAnnotation.element = constExpr.staticElement;
       Identifier typeName = constExpr.constructorName.type.name;
       SimpleIdentifier constructorName = constExpr.constructorName.name;
       if (typeName is SimpleIdentifier && constructorName != null) {
@@ skipping 403 matching lines @@
   static String _getElementIdentifier(String name, ReferenceKind kind) {
     if (kind == ReferenceKind.topLevelPropertyAccessor ||
         kind == ReferenceKind.propertyAccessor) {
       if (!name.endsWith('=')) {
         return name + '?';
       }
     }
     return name;
   }
 }