diff --git a/Library/Homebrew/cmd/deps.rb b/Library/Homebrew/cmd/deps.rb
index 7e05f8a1db..658b079022 100644
--- a/Library/Homebrew/cmd/deps.rb
+++ b/Library/Homebrew/cmd/deps.rb
@@ -24,7 +24,7 @@ module Homebrew
       puts_deps Formula.installed
     else
       all_deps = deps_for_formulae(ARGV.formulae, !ARGV.one?, &(mode.union? ? :| : :&))
-      all_deps.keep_if(&:installed?) if mode.installed?
+      all_deps = all_deps.select(&:installed?) if mode.installed?
       all_deps = all_deps.sort_by(&:name) unless mode.topo_order?
       puts all_deps
     end