1 files changed, 5 insertions, 0 deletions
diff --git a/lib/rdoc/options.rb b/lib/rdoc/options.rb
index 7b3a23ca5c..90415f0aa4 100644
--- a/lib/rdoc/options.rb
+++ b/lib/rdoc/options.rb
@@ -366,6 +366,11 @@ Usage: #{opt.program_name} [options] [names...]
       end
     end
 
+    if @pipe and not argv.empty? then
+      @pipe = false
+      ignored << '-p (with files)'
+    end
+
     unless ignored.empty? or quiet then
       $stderr.puts "invalid options: #{ignored.join ', '}"
       $stderr.puts '(invalid options are ignored)'