anchor.diff:      }
   
       // If the error came from a file, include the path.
  -    if (error is SpanException && error.span.sourceUrl != null) {
  +    if ((error is SpanException || error is SourceSpanException) &&
  +        error.span.sourceUrl != null) {
         errorJson["path"] = p.fromUri(error.span.sourceUrl);
       }
   
  
positive.code:   // spew a stack trace on our users.
    if (exception is SpanException) {
      error(exception.toString(useColors: canUseSpecialChars));
    } else {
      error(getErrorMessage(exception));
    }
  
negative.code: 
  import 'package:path/path.dart' as p;
  import 'package:source_maps/source_maps.dart';
  import 'package:source_span/source_span.dart';
  import 'package:stack_trace/stack_trace.dart';
  
  import 'exceptions.dart';
  