dart2js: Keep refined type for type checks

pkg/compiler/lib/src/ssa/nodes.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.
 
 import '../closure.dart';
 import '../common.dart';
 import '../common/backend_api.dart' show BackendClasses;
 import '../compiler.dart' show Compiler;
 import '../constants/constant_system.dart';
 import '../constants/values.dart';
@@ skipping 2821 matching lines @@
   final int kind;
   // [receiverTypeCheckSelector] is the selector used for a receiver type check
   // on open-coded operators, e.g. the not-null check on `x` in `x + 1` would be
   // compiled to the following, for which we need the selector `$add`.
   //
   //     if (typeof x != "number") x.$add();
   //
   final Selector receiverTypeCheckSelector;
 
   TypeMask checkedType; // Not final because we refine it.
+  TypeMask inputType; // Holds input type for codegen after HTypeKnown removal.
 
   HTypeConversion(
       this.typeExpression, this.kind, TypeMask type, HInstruction input,
       {this.receiverTypeCheckSelector})
       : checkedType = type,
         super(<HInstruction>[input], type) {
     assert(!isReceiverTypeCheck || receiverTypeCheckSelector != null);
     assert(typeExpression == null || !typeExpression.isTypedef);
     sourceElement = input.sourceElement;
   }
@@ skipping 647 matching lines @@
 class HDynamicType extends HRuntimeType {
   HDynamicType(DynamicType dartType, TypeMask instructionType)
       : super(const <HInstruction>[], dartType, instructionType);
 
   accept(HVisitor visitor) => visitor.visitDynamicType(this);
 
   int typeCode() => HInstruction.DYNAMIC_TYPE_TYPECODE;
 
   bool typeEquals(HInstruction other) => other is HDynamicType;
 }