Try incremental analysis before limiting invalidation.

pkg/analyzer/lib/src/context/context.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 analyzer.src.context.context;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ skipping 1761 matching lines @@
    */
   void _sourceRemoved(Source source) {
     _cache.remove(source);
     _removeFromPriorityOrder(source);
   }
 
   /**
    * TODO(scheglov) A hackish, limited incremental resolution implementation.
    */
   bool _tryPoorMansIncrementalResolution(Source unitSource, String newCode) {
-    if (AnalysisEngine.instance.limitInvalidationInTaskModel) {
-      return false;
-    }
     return PerformanceStatistics.incrementalAnalysis.makeCurrentWhile(() {
       incrementalResolutionValidation_lastUnitSource = null;
       incrementalResolutionValidation_lastLibrarySource = null;
       incrementalResolutionValidation_lastUnit = null;
       // prepare the entry
       CacheEntry sourceEntry = _cache.get(unitSource);
       if (sourceEntry == null) {
         return false;
       }
       // prepare the (only) library source
@@ skipping 232 matching lines @@
         new PendingFuture<T>(_context, target, computeValue);
     if (!pendingFuture.evaluate(entry)) {
       _context._pendingFutureTargets
           .putIfAbsent(target, () => <PendingFuture>[])
           .add(pendingFuture);
       scheduleComputation();
     }
     return pendingFuture.future;
   }
 }