From 0e3c11ea07e84616266602aaa9e4adcb24773fc8 Mon Sep 17 00:00:00 2001
From: Xu Cheng <xucheng@me.com>
Date: Tue, 16 Jun 2015 14:58:47 +0800
Subject: [PATCH] doctor: use Formula.installed directly

Before
```
brew doctor  9.83s user 0.52s system 76% cpu 13.563 total
```

After
```
brew doctor  0.25s user 0.16s system 9% cpu 4.332 total
```

Closes Homebrew/homebrew#40770.

Signed-off-by: Xu Cheng <xucheng@me.com>
---
 Library/Homebrew/cmd/doctor.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/cmd/doctor.rb b/Library/Homebrew/cmd/doctor.rb
index 55ebcd0ff2..2be9f18e07 100644
--- a/Library/Homebrew/cmd/doctor.rb
+++ b/Library/Homebrew/cmd/doctor.rb
@@ -927,8 +927,8 @@ end
 def check_for_linked_keg_only_brews
   return unless HOMEBREW_CELLAR.exist?
 
-  linked = Formula.select { |f|
-    f.keg_only? && f.installed? && __check_linked_brew(f)
+  linked = Formula.installed.select { |f|
+    f.keg_only? && __check_linked_brew(f)
   }
 
   unless linked.empty?