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

runtime/observatory/lib/src/elements/script_inset.dart

Index: runtime/observatory/lib/src/elements/script_inset.dart
diff --git a/runtime/observatory/lib/src/elements/script_inset.dart b/runtime/observatory/lib/src/elements/script_inset.dart
index 1b94f3837f25e9c73f6a81e062f9029af9c48032..0843a398a9568641187d3a9878d2fdefe64c2f21 100644
--- a/runtime/observatory/lib/src/elements/script_inset.dart
+++ b/runtime/observatory/lib/src/elements/script_inset.dart
@@ -597,12 +597,14 @@ class ScriptInsetElement extends ObservatoryElement {
     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) {