diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 5673c898a2..398f144133 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -61,11 +61,11 @@ class Formula
 
   def determine_active_spec
     case
-    when head && ARGV.build_head?        then head    # --HEAD
-    when devel && ARGV.build_devel?      then devel   # --devel
-    when stable                          then stable
-    when devel && stable.nil?            then devel   # devel-only
-    when head && stable.nil?             then head    # head-only
+    when head && ARGV.build_head?   then head    # --HEAD
+    when devel && ARGV.build_devel? then devel   # --devel
+    when stable                     then stable
+    when devel                      then devel
+    when head                       then head    # head-only
     else
       raise FormulaSpecificationError, "formulae require at least a URL"
     end