diff --git a/Library/Homebrew/superenv.rb b/Library/Homebrew/superenv.rb
index ba42a5604c..fbcc3eabc6 100644
--- a/Library/Homebrew/superenv.rb
+++ b/Library/Homebrew/superenv.rb
@@ -18,7 +18,7 @@ end
 def superenv?
   not MacOS::Xcode.bad_xcode_select_path? and # because xcrun won't work
   not MacOS::Xcode.folder.nil? and # because xcrun won't work
-  superenv_bin.directory? and
+  and superenv_bin and superenv_bin.directory? and
   not ARGV.include? "--env=std"
 end