diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index 14eb0e3f33660e0369354a24a0c946f3983ea5ff..4c869b04834c48e9a9bbd9a472791ec2dca071c8 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -192,11 +192,7 @@ class Keg
     path.parent
   end
 
-  if Pathname.method_defined?(:to_path)
-    alias to_path to_s
-  else
-    alias to_str to_s
-  end
+  alias to_path to_s
 
   def inspect
     "#<#{self.class.name}:#{path}>"