anchor.diff:        var newName = toCamelCase(name);
         _logger.warning('PolymerElement no longer recognizes attribute names with '
             'dashes such as "$name". Use "$newName" or "${newName.toLowerCase()}" '
  -          'instead (both forms are equivalent in HTML).', span);
  +          'instead (both forms are equivalent in HTML).', span: span);
         return false;
       }
       return true;
  
positive.code:           ' JavaScript event handler. Use the form '
            'on-event-name="handlerName" if you want a Dart handler '
            'that will automatically update the UI based on model changes.',
            node.attributeSpans[name]);
        return;
      }
  
      if (!_inPolymerElement) {
        _logger.warning('Inline event handlers are only supported inside '
            'declarations of <polymer-element>.', node.attributeSpans[name]);
      }
  
      var eventName = name.substring('on-'.length);
  
negative.code:         if (existing.hasConflict) continue;
          existing.hasConflict = true;
          logger.warning('duplicate definition for custom tag "$name".',
            span: existing.span);
          logger.warning('duplicate definition for custom tag "$name" '
            ' (second definition).', span: span);
          continue;
        }
  
  