diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index b65600893f..92bb779f8e 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -391,7 +391,7 @@ class Formula
   # @private
   def any_version_installed?
     require "tab"
-    rack.directory? && rack.subdirs.any? { |keg| (keg/Tab::FILENAME).file? }
+    installed_prefixes.any? { |keg| (keg/Tab::FILENAME).file? }
   end
 
   # @private
@@ -950,8 +950,7 @@ class Formula
         raise Migrator::MigrationNeededError.new(self)
       end
 
-      rack.subdirs.each do |keg_dir|
-        keg = Keg.new keg_dir
+      installed_kegs.each do |keg|
         version = keg.version
         all_versions << version
         older_version = pkg_version <= version
@@ -1297,22 +1296,19 @@ class Formula
       hsh["bottle"][spec_sym] = bottle_info
     end
 
-    if rack.directory?
-      rack.subdirs.each do |keg_path|
-        keg = Keg.new keg_path
-        tab = Tab.for_keg keg_path
+    installed_kegs.each do |keg|
+      tab = Tab.for_keg keg
 
-        hsh["installed"] << {
-          "version" => keg.version.to_s,
-          "used_options" => tab.used_options.as_flags,
-          "built_as_bottle" => tab.built_bottle,
-          "poured_from_bottle" => tab.poured_from_bottle
-        }
-      end
-
-      hsh["installed"] = hsh["installed"].sort_by { |i| Version.new(i["version"]) }
+      hsh["installed"] << {
+        "version" => keg.version.to_s,
+        "used_options" => tab.used_options.as_flags,
+        "built_as_bottle" => tab.built_bottle,
+        "poured_from_bottle" => tab.poured_from_bottle
+      }
     end
 
+    hsh["installed"] = hsh["installed"].sort_by { |i| Version.new(i["version"]) }
+
     hsh
   end