Compute more accurate bound on expected work when tracing.

pkg/compiler/lib/src/inferrer/node_tracer.dart

 // Copyright (c) 2013, 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.
 
 part of type_graph_inferrer;
 
 // A set of selectors we know do not escape the elements inside the
 // list.
 Set<String> doesNotEscapeListSet = new Set<String>.from(
   const <String>[
@@ skipping 86 matching lines @@
   // The current [TypeInformation] in the analysis.
   TypeInformation currentUser;
   bool continueAnalyzing = true;
 
   void addNewEscapeInformation(TypeInformation info) {
     if (flowsInto.contains(info)) return;
     flowsInto.add(info);
     workList.add(info);
   }
 
+  bool _wouldBeTooManyUsers(Iterable users) {
+    int seenSoFar = analyzedElements.length;
+    if (seenSoFar + users.length <= MAX_ANALYSIS_COUNT) return false;

[floitsch, 2014/11/17 14:52:57]

users is an iterable.
By asking `.length` you run through it. You might end up running through it
twice.

[herhut, 2014/11/17 15:12:45]

Actually, it is a Set. I just used Iterable because that is all I needed wrt.
functionality. I have exposed it as a Set now.

+    int actualWork = users.fold(0, (sum, user) {

[floitsch, 2014/11/17 14:52:57]

I think I would have gone with a simple `for` loop, but that got me thinking...
In the end I think a simple `where` is the most intuitive.

int actualWork = users
    .where((User user) => analyzedElements.contains(user.owner))
    .length;

[herhut, 2014/11/17 15:12:45]

Nice. Done.

+      return analyzedElements.contains(user.owner) ? sum : sum + 1;
+    });
+    return seenSoFar + actualWork > MAX_ANALYSIS_COUNT;
+  }
+
   void analyze() {
     // Collect the [TypeInformation] where the list can flow in,
     // as well as the operations done on all these [TypeInformation]s.
     addNewEscapeInformation(tracedType);
     while (!workList.isEmpty) {
       currentUser = workList.removeLast();
-      int expectedWork = analyzedElements.length + currentUser.users.length;
-      if (expectedWork > MAX_ANALYSIS_COUNT) {
+      if (_wouldBeTooManyUsers(currentUser.users)) {
         bailout('Too many users');
         break;
       }
       for (TypeInformation info in currentUser.users) {
         analyzedElements.add(info.owner);
         info.accept(this);
       }
       while (!listsToAnalyze.isEmpty) {
         analyzeStoredIntoList(listsToAnalyze.removeLast());
       }
@@ skipping 253 matching lines @@
     }
     if (isParameterOfListAddingMethod(info.element) ||
         isParameterOfMapAddingMethod(info.element)) {
       // These elements are being handled in
       // [visitDynamicCallSiteTypeInformation].
       return;
     }
     addNewEscapeInformation(info);
   }
 }