2 files changed, 6 insertions, 1 deletions
diff --git a/lib/irb.rb b/lib/irb.rb
index dcc160f140..b07bc80c95 100644
--- a/lib/irb.rb
+++ b/lib/irb.rb
@@ -703,7 +703,6 @@ end
 
 class Binding
   # :nodoc:
-  undef irb if method_defined?(:irb)
   def irb
     IRB.setup(eval("__FILE__"))
     workspace = IRB::WorkSpace.new(self)
diff --git a/prelude.rb b/prelude.rb
index c0a8dfccfa..a693f46156 100644
--- a/prelude.rb
+++ b/prelude.rb
@@ -140,6 +140,9 @@ class Binding
     require 'irb'
     irb
   end
+
+  # suppress redefinition warning
+  alias irb irb # :nodoc:
 end
 
 module Kernel
@@ -150,4 +153,7 @@ module Kernel
     require 'pp'
     pp(*objs)
   end
+
+  # suppress redefinition warning
+  alias pp pp # :nodoc:
 end