diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 35585b8991..e2a1ac2a23 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -99,7 +99,7 @@ class Formula
       @version='HEAD'
     end
 
-    raise if @url.nil?
+    raise "No url provided for formula #{name}" if @url.nil?
     @name=name
     validate_variable :name