Incremental compilation: set up inheritance.

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

Index: dart/pkg/compiler/lib/src/universe/universe.dart
diff --git a/dart/pkg/compiler/lib/src/universe/universe.dart b/dart/pkg/compiler/lib/src/universe/universe.dart
index e5e3915d8518b57786f3721788cf218bfb612466..5b60d70850bb7794a34e229552e257cecbfe88b0 100644
--- a/dart/pkg/compiler/lib/src/universe/universe.dart
+++ b/dart/pkg/compiler/lib/src/universe/universe.dart
@@ -747,6 +747,13 @@ class TypedSelector extends Selector {
       new Map<Selector, Map<TypeMask, TypedSelector>>();
 
   factory TypedSelector(TypeMask mask, Selector selector, World world) {
+    if (!world.hasClosedWorldAssumption) {

[Johnni Winther, 2014/11/17 09:56:32]

Add a TODO (for me) to improve the use of TypedSelector in an open world.

+      bool isNullable = mask.isNullable;
+      mask = world.compiler.typesTask.dynamicType;
+      if (isNullable) {
+        mask = mask.nullable();
+      }
+    }
     // TODO(johnniwinther): Allow more TypeSelector kinds during resoluton.
     assert(world.isClosed || mask.isExact);
     if (selector.mask == mask) return selector;