Copy all fields of NullCheck

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

 // Copyright (c) 2013, 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;
 
 import 'dart:collection';
 import 'cps_fragment.dart' show CpsFragment;
 import '../constants/values.dart' as values;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
@@ skipping 832 matching lines @@
 
   Primitive get effectiveDefinition => object.definition.effectiveDefinition;
 }
 
 /// Throw an exception if [value] is `null`.
 ///
 /// Returns [value] so this can be used to restrict code motion.
 ///
 /// In the simplest form this compiles to `value.toString;`.
 ///
-/// If [selector] is set, `toString` is replaced with the (possibly minified)
-/// invocation name of the selector.  This can be shorter and generate a more
-/// meaningful error message, but is expensive if [value] is non-null and does
-/// not have that property at runtime.
+/// [selector] holds the selector that is the cause of the null check. This is
+/// usually a method that was inlined where [value] the receiver.
+///
+/// If [selector] is set and [useSelector] is true, `toString` is replaced with
+/// the (possibly minified) invocation name of the selector.  This can be
+/// shorter and generate a more meaningful error message, but is expensive if
+/// [value] is non-null and does not have that property at runtime.
 ///
 /// If [condition] is set, it is assumed that [condition] is true if and only
 /// if [value] is null.  The check then compiles to:
 ///
 ///     if (condition) value.toString;  (or .selector if non-null)
 ///
 /// The latter form is useful when [condition] is a form understood by the JS
 /// runtime, such as a `typeof` test.
 class NullCheck extends Primitive {
   final Reference<Primitive> value;
-  Selector selector;
-  Reference<Primitive> condition;
+  final Selector selector;
+  final bool useSelector;
+  final Reference<Primitive> condition;
   final SourceInformation sourceInformation;
 
-  NullCheck(Primitive value, this.sourceInformation)
-      : this.value = new Reference<Primitive>(value);
+  NullCheck(Primitive value, this.sourceInformation,
+            {Primitive condition,
+             this.selector,
+             this.useSelector: false})
+      : this.value = new Reference<Primitive>(value),
+        this.condition =
+            condition == null ? null : new Reference<Primitive>(condition);
 
   NullCheck.guarded(Primitive condition, Primitive value, this.selector,
         this.sourceInformation)
       : this.condition = new Reference<Primitive>(condition),
-        this.value = new Reference<Primitive>(value);
+        this.value = new Reference<Primitive>(value),
+        this.useSelector = true;
 
   bool get isSafeForElimination => false;
   bool get isSafeForReordering => false;
   bool get hasValue => true;
 
   accept(Visitor visitor) => visitor.visitNullCheck(this);
 
   void setParentPointers() {
     value.parent = this;
     if (condition != null) {
@@ skipping 1801 matching lines @@
           node.sourceInformation);
     } else {
       return new BoundsCheck(getCopy(node.object), getCopy(node.index),
           getCopy(node.length),
           node.checks,
           node.sourceInformation);
     }
   }
 
   Definition visitNullCheck(NullCheck node) {
-    return new NullCheck(getCopy(node.value), node.sourceInformation);
+    return new NullCheck(getCopy(node.value), node.sourceInformation,
+        condition: node.condition == null ? null : getCopy(node.condition),
+        selector: node.selector,
+        useSelector: node.useSelector);
   }
 
   Definition visitForeignCode(ForeignCode node) {
     return new ForeignCode(node.codeTemplate, node.type,
         getList(node.arguments),
         node.nativeBehavior,
         dependency: node.dependency);
   }
 }
 
@@ skipping 127 matching lines @@
     plug(new Branch.loose(_definitions.getCopy(node.condition),
         _copies[node.trueContinuation.definition],
         _copies[node.falseContinuation.definition])
       ..isStrictCheck = node.isStrictCheck);
   }
 
   visitUnreachable(Unreachable node) {
     plug(new Unreachable());
   }
 }