diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 07692ff894..6a3a053c88 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -233,7 +233,7 @@ end
 
 class GithubGistFormula <ScriptFileFormula
   def initialize
-    super File.basename(url)
+    super File.basename(self.class.url)
     @version=File.basename(File.dirname(url))[0,6]
   end
 end