Fix memory leak in incremental resolver

pkg/analyzer/lib/src/context/cache.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.cache;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_collection.dart';
 import 'package:analyzer/src/task/model.dart';
 import 'package:analyzer/task/model.dart';
 
+import 'package:analyzer/src/dart/element/element.dart' show ElementImpl;
+
 /**
  * Return `true` if the given [target] is a priority one.
  */
 typedef bool IsPriorityAnalysisTarget(AnalysisTarget target);
 
 /**
  * An LRU cache of results produced by analysis.
  */
 class AnalysisCache {
   /**
@@ skipping 350 matching lines @@
     if (data == null) {
       return CacheState.INVALID;
     }
     return data.state;
   }
 
   /**
    * Return the value of the result represented by the given [descriptor], or
    * the default value for the result if this entry does not have a valid value.
    */
-  dynamic /*=V*/ getValue /*<V>*/ (ResultDescriptor /*<V>*/ descriptor) {
+  dynamic/*=V*/ getValue/*<V>*/(ResultDescriptor/*<V>*/ descriptor) {
     ResultData data = _resultMap[descriptor];
     if (data == null) {
       return descriptor.defaultValue;
     }
     if (_partition != null) {
       _partition.resultAccessed(target, descriptor);
     }
     return data.value;
   }
 
@@ skipping 77 matching lines @@
         //
         data.value = descriptor.defaultValue;
       }
     }
   }
 
   /**
    * Set the value of the result represented by the given [descriptor] to the
    * given [value].
    */
-  void setValue /*<V>*/ (ResultDescriptor /*<V>*/ descriptor,
-      dynamic /*=V*/ value, List<TargetedResult> dependedOn) {
+  void setValue/*<V>*/(ResultDescriptor/*<V>*/ descriptor, dynamic/*=V*/ value,
+      List<TargetedResult> dependedOn) {
 //    {
 //      String valueStr = '$value';
 //      if (valueStr.length > 20) {
 //        valueStr = valueStr.substring(0, 20) + '...';
 //      }
 //      valueStr = valueStr.replaceAll('\n', '\\n');
 //      print(
 //          'setValue $descriptor for $target value=$valueStr $dependedOn=$dependedOn');
 //    }
     _validateStateChange(descriptor, CacheState.VALID);
@@ skipping 78 matching lines @@
       ResultData data = _partition._getDataFor(dependedOnResult);
       if (data != null && deltaResult != DeltaResult.KEEP_CONTINUE) {
         data.dependentResults.remove(thisResult);
       }
     }
     // Invalidate results that depend on this result.
     _invalidateDependentResults(id, thisData, delta, level + 1);
     // If empty and not explicitly added, remove the entry altogether.
     if (_resultMap.isEmpty && !explicitlyAdded) {
       _partition.entryMap.remove(target);
+      if (target is ElementImpl) {
+        // Allow mutations now that it's no longer a map key.
+        (target as ElementImpl).frozen = false;
+      }
       _partition._removeIfSource(target);
     }
     // Notify controller.
     _partition.onResultInvalidated
         .add(new InvalidatedResult(this, descriptor, thisData.value));
   }
 
   /**
    * Invalidates all the results of this entry, with propagation.
    */
@@ skipping 320 matching lines @@
    * Puts the given [entry] into the partition.
    */
   void put(CacheEntry entry) {
     AnalysisTarget target = entry.target;
     if (entry._partition != null) {
       throw new StateError(
           'The entry for $target is already in ${entry._partition}');
     }
     entry._partition = this;
     entry.fixExceptionState();
+    if (target is ElementImpl) {
+      // Detect attempts to mutate the map key.
+      target.frozen = true;
+    }
     entryMap[target] = entry;
     _addIfSource(target);
   }
 
   /**
    * Remove all information related to the given [target] from this partition.
    * Return the entry associated with the target, or `null` if there was cache
    * entry for the target.
    */
   CacheEntry remove(AnalysisTarget target) {
@@ skipping 317 matching lines @@
   void resultAccessed(TargetedResult result) {}
 
   @override
   List<TargetedResult> resultStored(TargetedResult newResult, newValue) {
     return TargetedResult.EMPTY_LIST;
   }
 
   @override
   void targetRemoved(AnalysisTarget target) {}
 }