ActiveRecord::Base#has_errors?

I really hate typing unless @foo.errors.blank? when I really mean if @user.has_errors? and thought this might make a good patch on Rails. Calling #invalid? actually clears the errors and redoes the validation which isn't the behavior I want here. I just want to know that the object has errors.

I didn't add tests because it seems a really simple patch and it would probably require mocha to assert that the validations don't get run. I'm completely open to writing tests if need be though.