diff --git a/Library/Homebrew/dependency_collector.rb b/Library/Homebrew/dependency_collector.rb
index 7a8d712de8..f0df900650 100644
--- a/Library/Homebrew/dependency_collector.rb
+++ b/Library/Homebrew/dependency_collector.rb
@@ -123,7 +123,7 @@ class DependencyCollector
     when :ld64       then LD64Dependency.new if MacOS.version < :leopard
     when :ant        then ant_dep(spec, tags)
     else
-      raise "Unsupported special dependency #{spec.inspect}"
+      raise ArgumentError, "Unsupported special dependency #{spec.inspect}"
     end
   end