Skip adding line based range data for ranges that don't map to a line.

runtime/observatory/lib/src/elements/script_inset.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 script_inset_element;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:math';
 import 'observatory_element.dart';
@@ skipping 579 matching lines @@
     var sourceReport = await script.isolate.getSourceReport(
         reports,
         script, startPos, endPos);
     _possibleBreakpointLines = getPossibleBreakpointLines(sourceReport, script);
     _rangeMap.clear();
     _callSites.clear();
     _profileMap.clear();
     for (var range in sourceReport['ranges']) {
       int startLine = script.tokenToLine(range['startPos']);
       int endLine = script.tokenToLine(range['endPos']);
-      for (var line = startLine; line <= endLine; line++) {
-        var rangeList = _rangeMap[line];
-        if (rangeList == null) {
-          _rangeMap[line] = [range];
-        } else {
-          rangeList.add(range);
+      if ((startLine != null) && (endLine != null)) {

[turnidge, 2016/05/09 19:20:12]

Can you add a TODO(turnidge) here to track down this issue?

[Cutch, 2016/05/09 20:40:04]

Done.

+        for (var line = startLine; line <= endLine; line++) {
+          var rangeList = _rangeMap[line];
+          if (rangeList == null) {
+            _rangeMap[line] = [range];
+          } else {
+            rangeList.add(range);
+          }
         }
       }
       if (_includeProfile && range['profile'] != null) {
         List positions = range['profile']['positions'];
         List exclusiveTicks = range['profile']['exclusiveTicks'];
         List inclusiveTicks = range['profile']['inclusiveTicks'];
         int sampleCount = range['profile']['metadata']['sampleCount'];
         assert(positions.length == exclusiveTicks.length);
         assert(positions.length == inclusiveTicks.length);
         for (int i = 0; i < positions.length; i++) {
@@ skipping 750 matching lines @@
 class SourceInsetElement extends PolymerElement {
   SourceInsetElement.created() : super.created();
 
   @published SourceLocation location;
   @published String height = null;
   @published int currentPos;
   @published bool inDebuggerContext = false;
   @published ObservableList variables;
   @published Element scroller;
 }