Implement is-checks against type variables.

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

Index: sdk/lib/_internal/compiler/implementation/world.dart
diff --git a/sdk/lib/_internal/compiler/implementation/world.dart b/sdk/lib/_internal/compiler/implementation/world.dart
index 271629bf64132666df45a3b3aba08074886ca86e..4eafbf72229bb9f3388676120ff3c74955f66ccd 100644
--- a/sdk/lib/_internal/compiler/implementation/world.dart
+++ b/sdk/lib/_internal/compiler/implementation/world.dart
@@ -10,6 +10,7 @@ class World {
   final Map<ClassElement, Set<MixinApplicationElement>> mixinUses;
   final Map<ClassElement, Set<ClassElement>> typesImplementedBySubclasses;
   final Set<ClassElement> classesNeedingRti;
+  final Set<ClassElement> usedFactoriesOfAbstractClasses;

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

Store the factories instead, as implied by the name?

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

Obsolete.

   final Map<ClassElement, Set<ClassElement>> rtiDependencies;
   final FullFunctionSet allFunctions;
 
@@ -19,6 +20,7 @@ class World {
         typesImplementedBySubclasses =
             new Map<ClassElement, Set<ClassElement>>(),
         classesNeedingRti = new Set<ClassElement>(),
+        usedFactoriesOfAbstractClasses = new Set<ClassElement>(),
         rtiDependencies = new Map<ClassElement, Set<ClassElement>>(),
         allFunctions = new FullFunctionSet(compiler),
         this.compiler = compiler;
@@ -79,14 +81,32 @@ class World {
       }
     }
 
+    Set<ClassElement> classesUsingTypeVariableTests = new Set<ClassElement>();
     compiler.resolverWorld.isChecks.forEach((DartType type) {
-      if (type is InterfaceType) {
+      if (type.kind == TypeKind.TYPE_VARIABLE) {
+        TypeVariableElement variable = type.element;
+        classesUsingTypeVariableTests.add(variable.enclosingElement);
+      }
+    });
+    compiler.resolverWorld.addImplicitChecks(classesUsingTypeVariableTests);
+    compiler.resolverWorld.isChecks.forEach((DartType type) {
+      if (type.kind == TypeKind.INTERFACE) {
         InterfaceType itf = type;
         if (!itf.isRaw) {
           potentiallyAddForRti(itf.element);
         }
+      } else if (type.kind == TypeKind.TYPE_VARIABLE) {
+        TypeVariableElement variable = type.element;
+        potentiallyAddForRti(variable.enclosingElement);
       }
     });
+
+    // TODO(karlklose): if we know all targets of factories for the abstract
+    // class, we should check whether one of these targets needs runtime type
+    // information before adding the class.
+    usedFactoriesOfAbstractClasses.forEach((ClassElement cls) {
+      potentiallyAddForRti(cls);
+    });
   }
 
   void registerMixinUse(MixinApplicationElement mixinApplication,
@@ -170,4 +190,8 @@ class World {
         .map((Element member) => member.getEnclosingClass())
         .where((ClassElement holder) => !identical(holder, objectClass));
   }
+
+  void registerUsedFactoriesOfAbstractClasses(ClassElement cls) {
+    usedFactoriesOfAbstractClasses.add(cls);
+  }
 }