Add source mapping info to loops.

lib/compiler/implementation/ssa/codegen.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.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 767 matching lines @@
       generateStatements(info.body);
       currentBlockInformation = oldInfo;
     } else {
       generateStatements(info.body);
     }
   }
 
   bool visitLoopInfo(HLoopBlockInformation info) {
     HExpressionInformation condition = info.condition;
     bool isConditionExpression = isJSCondition(condition);
+    buffer.setSourceLocation(work.element, info.sourcePosition.getBeginToken());
 
     switch (info.kind) {
       // Treate all three "test-first" loops the same way.
       case HLoopBlockInformation.FOR_LOOP:
       case HLoopBlockInformation.WHILE_LOOP:
       case HLoopBlockInformation.FOR_IN_LOOP: {
         HBlockInformation initialization = info.initializer;
         int initializationType = TYPE_STATEMENT;
         if (initialization !== null) {
           initializationType = expressionType(initialization);
@@ skipping 97 matching lines @@
           use(condition.conditionExpression, JSPrecedence.PREFIX_PRECEDENCE);
           buffer.add(");\n");
         }
         break;
       }
       default:
         compiler.internalError(
           'Unexpected loop kind: ${info.kind}',
           instruction: condition.conditionExpression);
     }
+    buffer.setSourceLocation(work.element, info.sourcePosition.getEndToken());
     return true;
   }
 
   bool visitLabeledBlockInfo(HLabeledBlockInformation labeledBlockInfo) {
     preLabeledBlock(labeledBlockInfo);
     addIndentation();
     Link<Element> continueOverrides = const EmptyLink<Element>();
     // If [labeledBlockInfo.isContinue], the block is an artificial
     // block around the body of a loop with an update block, so that
     // continues of the loop can be written as breaks of the body
@@ skipping 2227 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }