dart2js cps: Type casts and related changes to type propagation.

pkg/compiler/lib/src/cps_ir/cps_ir_nodes_sexpr.dart

 // Copyright (c) 2014, 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.
 
 library dart2js.ir_nodes_sexpr;
 
 import '../constants/values.dart';
 import '../util/util.dart';
 import 'cps_ir_nodes.dart';
 
@@ skipping 184 matching lines @@
     return '$indentation(Rethrow)';
   }
 
   String visitBranch(Branch node) {
     String condition = visit(node.condition);
     String trueCont = access(node.trueContinuation);
     String falseCont = access(node.falseContinuation);
     return '$indentation(Branch $condition $trueCont $falseCont)';
   }
 
+  String visitUnreachable(Unreachable node) {
+    return '$indentation(Unreachable)';
+  }
+
   String visitConstant(Constant node) {
     String value = node.value.accept(new ConstantStringifier(), null);
     return '(Constant $value)';
   }
 
   String visitCreateFunction(CreateFunction node) {
     String function =
         indentBlock(() => indentBlock(() => visit(node.definition)));
     return '(CreateFunction\n$function)';
   }
 
   String visitContinuation(Continuation node) {
     // Continuations are visited directly in visitLetCont.
     return '(Unexpected Continuation)';
   }
 
   String visitGetMutableVariable(GetMutableVariable node) {
     return '(GetMutableVariable ${access(node.variable)})';
   }
 
   String visitSetMutableVariable(SetMutableVariable node) {
     String value = access(node.value);
     String body = indentBlock(() => visit(node.body));
     return '$indentation(SetMutableVariable ${access(node.variable)} '
            '$value\n$body)';
   }
 
-  String visitTypeOperator(TypeOperator node) {
+  String visitTypeCast(TypeCast node) {
     String value = access(node.value);
     String cont = access(node.continuation);
-    String operator = node.isTypeTest ? 'is' : 'as';
     String typeArguments = node.typeArguments.map(access).join(' ');
-    return '$indentation(TypeOperator $operator $value ${node.type} '
-           '($typeArguments) $cont)';
+    return '$indentation(TypeCast $value ${node.type} ($typeArguments) $cont)';
+  }
+
+  String visitTypeTest(TypeTest node) {
+    String value = access(node.value);
+    String typeArguments = node.typeArguments.map(access).join(' ');
+    return '(TypeTest $value ${node.type} ($typeArguments))';
   }
 
   String visitLiteralList(LiteralList node) {
     String values = node.values.map(access).join(' ');
     return '(LiteralList ($values))';
   }
 
   String visitLiteralMap(LiteralMap node) {
     String keys = node.entries.map((e) => access(e.key)).join(' ');
     String values = node.entries.map((e) => access(e.value)).join(' ');
@@ skipping 188 matching lines @@
   void setReturnContinuation(Continuation node) {
     assert(!_names.containsKey(node) || _names[node] == 'return');
     _names[node] = 'return';
   }
 
   String getName(Node node) {
     if (!_names.containsKey(node)) return 'MISSING_NAME';
     return _names[node];
   }
 }