diff --git a/Library/Homebrew/build_options.rb b/Library/Homebrew/build_options.rb
index 83afe362e9..3c8c81eb21 100644
--- a/Library/Homebrew/build_options.rb
+++ b/Library/Homebrew/build_options.rb
@@ -132,7 +132,8 @@ class BuildOptions
   end
 
   def opposite_of option
-    option = Option.new option
+    option = Option.new(option) unless Option == option
+
     if option.name =~ /^with-(.+)$/
       Option.new("without-#{$1}")
     elsif option.name =~ /^without-(.+)$/