Compute more accurate bound on expected work when tracing.

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

Index: pkg/compiler/lib/src/inferrer/node_tracer.dart
diff --git a/pkg/compiler/lib/src/inferrer/node_tracer.dart b/pkg/compiler/lib/src/inferrer/node_tracer.dart
index e5905ff2320ec7b1831296f39359afea7043de65..16f4185bf61565a78de47a2ba814845259bbe776 100644
--- a/pkg/compiler/lib/src/inferrer/node_tracer.dart
+++ b/pkg/compiler/lib/src/inferrer/node_tracer.dart
@@ -104,14 +104,22 @@ abstract class TracerVisitor<T extends TypeInformation>
     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;
       }