Fix checked mode.

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2011, 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.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 2217 matching lines @@
   }
 
   HType get guaranteedType() => type;
 
   accept(HVisitor visitor) => visitor.visitTypeConversion(this);
 
   bool hasSideEffects() => checked;
 }
 
 class HStringConcat extends HInstruction {
-  HStringConcat(HInstruction left, HInstrunction right)
+  final Node node;
+  HStringConcat(HInstruction left, HInstruction right, this.node)
       : super(<HInstruction>[left, right]);
   HType get guaranteedType() => HType.STRING;
 
   HInstruction get left() => inputs[0];
   HInstruction get right() => inputs[1];
 
   accept(HVisitor visitor) => visitor.visitStringConcat(this);
   toString() => "string concat";
 }
 
@@ skipping 314 matching lines @@
   HBasicBlock get start() => expression.start;
   HBasicBlock get end() {
     // We don't create a switch block if there are no cases.
     assert(!statements.isEmpty());
     return statements.last().end;
   }
 
   bool accept(HStatementInformationVisitor visitor) =>
       visitor.visitSwitchInfo(this);
 }