Add a type kind to TypedSelector. A typed selector can either be

sdk/lib/_internal/compiler/implementation/ssa/optimize.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 abstract class OptimizationPhase {
   String get name;
   void visitGraph(HGraph graph);
 }
@@ skipping 368 matching lines @@
     if (isFixedSizeListConstructor(node)) {
       node.guaranteedType = HType.FIXED_ARRAY;
     }
     return node;
   }
 
   HInstruction visitInvokeDynamicMethod(HInvokeDynamicMethod node) {
     if (node.isInterceptorCall) return handleInterceptorCall(node);
     HType receiverType = types[node.receiver];
     if (receiverType.isExact()) {
-      HBoundedType type = receiverType;
-      Element element = type.lookupMember(node.selector.name);
+      Element element = receiverType.lookupMember(node.selector.name, compiler);
       // TODO(ngeoffray): Also fold if it's a getter or variable.
       if (element != null && element.isFunction()) {
         if (node.selector.applies(element, compiler)) {
           FunctionElement method = element;
           FunctionSignature parameters = method.computeSignature(compiler);
           if (parameters.optionalParameterCount == 0) {
             node.element = element;
           }
           // TODO(ngeoffray): If the method has optional parameters,
           // we should pass the default values here.
@@ skipping 868 matching lines @@
 
     HTypeConversion newInput = new HTypeConversion(convertedType, input);
     dominator.addBefore(dominator.first, newInput);
     dominatedUsers.forEach((HInstruction user) {
       user.changeUse(input, newInput);
     });
   }
 
   void visitIs(HIs instruction) {
     HInstruction input = instruction.expression;
-    HType convertedType =
-        new HType.fromBoundedType(instruction.typeExpression, compiler);
+    HType convertedType = new HType.nonNullSubtype(
+        instruction.typeExpression, compiler);
 
     List<HInstruction> ifUsers = <HInstruction>[];
     List<HInstruction> notIfUsers = <HInstruction>[];
 
     for (HInstruction user in instruction.usedBy) {
       if (user is HIf) {
         ifUsers.add(user);
       } else if (user is HNot) {
         for (HInstruction notUser in user.usedBy) {
           if (notUser is HIf) notIfUsers.add(notUser);
@@ skipping 245 matching lines @@
     HBasicBlock block = user.block;
     block.addAfter(user, interceptor);
     block.rewrite(user, interceptor);
     block.remove(user);
 
     // The interceptor will be removed in the dead code elimination
     // phase. Note that removing it here would not work because of how
     // the [visitBasicBlock] is implemented.
   }
 }