diff --git a/Library/Homebrew/keg.rb b/Library/Homebrew/keg.rb
index b9ca83953a..8fdc78b4ec 100644
--- a/Library/Homebrew/keg.rb
+++ b/Library/Homebrew/keg.rb
@@ -24,14 +24,15 @@
 class Keg <Pathname
   def initialize path
     super path
-    raise "#{to_s} is not a valid keg" unless parent.parent == HOMEBREW_CELLAR
+    raise "#{to_s} is not a valid keg" unless parent.parent.realpath == HOMEBREW_CELLAR.realpath
     raise "#{to_s} is not a directory" unless directory?
   end
 
   # if path is a file in a keg then this will return the containing Keg object
   def self.for path
+    path = path.realpath
     while not path.root?
-      return Keg.new(path) if path.parent.parent == HOMEBREW_CELLAR
+      return Keg.new(path) if path.parent.parent == HOMEBREW_CELLAR.realpath
       path = path.parent.realpath # realpath() prevents root? failing
     end
     raise "#{path} is not inside a keg"