diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 5b89f487fd..67f2f9f93a 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -935,7 +935,7 @@ class Formula
 
       if oldname && !rack.exist? && (dir = HOMEBREW_CELLAR/oldname).directory? &&
         !dir.subdirs.empty? && tap == Tab.for_keg(dir.subdirs.first).tap
-        raise Migrator::MigrationNeededError.new(f)
+        raise Migrator::MigrationNeededError.new(self)
       end
 
       rack.subdirs.each do |keg_dir|