1 files changed, 9 insertions, 19 deletions
diff --git a/activesupport/lib/active_support/core_ext/object/inclusion.rb b/activesupport/lib/active_support/core_ext/object/inclusion.rb
index 3fec465ec0..b5671f66d0 100644
--- a/activesupport/lib/active_support/core_ext/object/inclusion.rb
+++ b/activesupport/lib/active_support/core_ext/object/inclusion.rb
@@ -1,25 +1,15 @@
 class Object
-  # Returns true if this object is included in the argument(s). Argument must be
-  # any object which responds to +#include?+ or optionally, multiple arguments can be passed in. Usage:
+  # Returns true if this object is included in the argument. Argument must be
+  # any object which responds to +#include?+. Usage:
   #
-  #   characters = ['Konata', 'Kagami', 'Tsukasa']
-  #   'Konata'.in?(characters) # => true
+  #   characters = ["Konata", "Kagami", "Tsukasa"]
+  #   "Konata".in?(characters) # => true
   #
-  #   character = 'Konata'
-  #   character.in?('Konata', 'Kagami', 'Tsukasa') # => true
-  #
-  # This will throw an ArgumentError if a single argument is passed in and it doesn't respond
+  # This will throw an ArgumentError if the argument doesn't respond
   # to +#include?+.
-  def in?(*args)
-    if args.length > 1
-      args.include? self
-    else
-      another_object = args.first
-      if another_object.respond_to? :include?
-        another_object.include? self
-      else
-        raise ArgumentError.new 'The single parameter passed to #in? must respond to #include?'
-      end
-    end
+  def in?(another_object)
+    another_object.include?(self)
+  rescue NoMethodError
+    raise ArgumentError.new("The parameter passed to #in? must respond to #include?")
   end
 end