Enqueue superclasses instead of supertypes.

pkg/compiler/lib/src/universe/class_set.dart

Index: pkg/compiler/lib/src/universe/class_set.dart
diff --git a/pkg/compiler/lib/src/universe/class_set.dart b/pkg/compiler/lib/src/universe/class_set.dart
index d19b2c1ceff8cd1cc655b6d0d016c9761c89a1ac..6cafa09f423bcf9ebed44c358b1217ebdafffc3e 100644
--- a/pkg/compiler/lib/src/universe/class_set.dart
+++ b/pkg/compiler/lib/src/universe/class_set.dart
@@ -101,27 +101,50 @@ class ClassHierarchyNode {
         includeUninstantiated: includeUninstantiated);
   }
 
-  void dump(StringBuffer sb, String indentation) {
-    sb.write('$indentation$cls:[');
+  void printOn(StringBuffer sb, String indentation,
+               {bool instantiatedOnly: false}) {
+    sb.write('$indentation$cls');
+    if (isDirectlyInstantiated) {
+      sb.write(' directly');
+    }
+    if (isIndirectlyInstantiated) {
+      sb.write(' indirectly');
+    }
+    sb.write(' [');
     if (_directSubclasses.isEmpty) {
       sb.write(']');
     } else {
-      sb.write('\n');
       bool needsComma = false;
       for (Link<ClassHierarchyNode> link = _directSubclasses;
            !link.isEmpty;
            link = link.tail) {
+        if (instantiatedOnly && !link.head.isInstantiated) {
+          continue;
+        }
         if (needsComma) {
           sb.write(',\n');
+        } else {
+          sb.write('\n');
         }
-        link.head.dump(sb, '$indentation  ');
+        link.head.printOn(
+            sb, '$indentation  ', instantiatedOnly: instantiatedOnly);
         needsComma = true;
       }
-      sb.write('\n');
-      sb.write('$indentation]');
+      if (needsComma) {
+        sb.write('\n');
+        sb.write('$indentation]');
+      } else {
+        sb.write(']');
+      }
     }
   }
 
+  String dump({String indentation: '', bool instantiatedOnly: false}) {
+    StringBuffer sb = new StringBuffer();
+    printOn(sb, indentation, instantiatedOnly: instantiatedOnly);
+    return sb.toString();
+  }
+
   String toString() => cls.toString();
 }
 
@@ -274,11 +297,11 @@ class ClassSet {
   String toString() {
     StringBuffer sb = new StringBuffer();
     sb.write('[\n');
-    node.dump(sb, '  ');
+    node.printOn(sb, '  ');
     sb.write('\n');
     if (_directSubtypes != null) {
       for (ClassHierarchyNode node in _directSubtypes) {
-        node.dump(sb, '  ');
+        node.printOn(sb, '  ');
         sb.write('\n');
       }
     }