Implement is-checks against type variables.

sdk/lib/_internal/compiler/implementation/enqueue.dart

Index: sdk/lib/_internal/compiler/implementation/enqueue.dart
diff --git a/sdk/lib/_internal/compiler/implementation/enqueue.dart b/sdk/lib/_internal/compiler/implementation/enqueue.dart
index 1036a57eb779e6d256f3c1da586785959dd3f464..2e6eb201b7bf20fe7095693b28e211567e89ce38 100644
--- a/sdk/lib/_internal/compiler/implementation/enqueue.dart
+++ b/sdk/lib/_internal/compiler/implementation/enqueue.dart
@@ -61,6 +61,15 @@ abstract class Enqueuer {
 
     if (!addElementToWorkList(element, elements)) return;
 
+    if (element.isFactoryConstructor()) {
+      ClassElement cls = element.getEnclosingClass();
+      // For factories (and instantiations of [List]), the target is abstract.
+      // Since we may need the type arguments for constructing the instance,
+      // we register the class to be added to the classes needing rti.
+      compiler.world.registerUsedFactoriesOfAbstractClasses(cls);
+      compiler.backend.registerSetRuntimeType();

[ngeoffray, 2013/02/27 12:36:28]

This (registerSetRuntimeType) should be done elsewhere, when we realize the type
arguments are actually needed.

[karlklose, 2013/02/27 16:11:32]

Obsolete.

+    }
+
     // Enable runtime type support if we discover a getter called runtimeType.
     // We have to enable runtime type before hitting the codegen, so
     // that constructors know whether they need to generate code for
@@ -86,6 +95,11 @@ abstract class Enqueuer {
   // the work list'?
   bool addElementToWorkList(Element element, [TreeElements elements]);
 
+  void registerInstantiatedType(InterfaceType type) {
+    universe.instantiatedTypes.add(type);
+    registerInstantiatedClass(type.element);
+  }
+
   void registerInstantiatedClass(ClassElement cls) {
     if (universe.instantiatedClasses.contains(cls)) return;
     if (!cls.isAbstract(compiler)) {