[kernel] Position on switch expression

pkg/kernel/lib/binary/ast_from_binary.dart

 // Copyright (c) 2016, 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 kernel.ast_from_binary;
 
 import 'dart:convert';
 import 'dart:typed_data';
 
 import '../ast.dart';
 import '../transformations/flags.dart';
@@ skipping 1028 matching lines @@
         var offset = readOffset();
         var bodyOffset = readOffset();
         var variable = readAndPushVariableDeclaration();
         var iterable = readExpression();
         var body = readStatement();
         variableStack.length = variableStackHeight;
         return new ForInStatement(variable, iterable, body, isAsync: isAsync)
           ..fileOffset = offset
           ..bodyOffset = bodyOffset;
       case Tag.SwitchStatement:
+        var offset = readOffset();
         var expression = readExpression();
         int count = readUInt();
         List<SwitchCase> cases =
             new List<SwitchCase>.generate(count, (i) => new SwitchCase.empty());
         switchCaseStack.addAll(cases);
         for (int i = 0; i < cases.length; ++i) {
           var caseNode = cases[i];
           int length = readUInt();
           caseNode.expressions.length = length;
           caseNode.expressionOffsets.length = length;
           for (int i = 0; i < length; ++i) {
             caseNode.expressionOffsets[i] = readOffset();
             caseNode.expressions[i] = readExpression()..parent = caseNode;
           }
           caseNode.isDefault = readByte() == 1;
           caseNode.body = readStatement()..parent = caseNode;
         }
         switchCaseStack.length -= count;
-        return new SwitchStatement(expression, cases);
+        return new SwitchStatement(expression, cases)..fileOffset = offset;
       case Tag.ContinueSwitchStatement:
         int index = readUInt();
         return new ContinueSwitchStatement(switchCaseStack[index]);
       case Tag.IfStatement:
         return new IfStatement(
             readExpression(), readStatement(), readStatementOrNullIfEmpty());
       case Tag.ReturnStatement:
         int offset = readOffset();
         return new ReturnStatement(readExpressionOption())..fileOffset = offset;
       case Tag.TryCatch:
@@ skipping 199 matching lines @@
       ..fileOffset = offset
       ..fileEqualsOffset = fileEqualsOffset;
   }
 
   int readOffset() {
     // Offset is saved as unsigned,
     // but actually ranges from -1 and up (thus the -1)
     return readUInt() - 1;
   }
 }