diff --git a/lib/rdoc/top_level.rb b/lib/rdoc/top_level.rb
index 6186722772..b8d4506ec8 100644
--- a/lib/rdoc/top_level.rb
+++ b/lib/rdoc/top_level.rb
@@ -272,7 +272,7 @@ def search_record
   # Is this TopLevel from a text file instead of a source code file?
 
   def text?
-    @parser and @parser.ancestors.include? RDoc::Parser::Text
+    @parser and @parser.include? RDoc::Parser::Text
   end
 
   def to_s # :nodoc: