Using safe mode with create! (Tag.safely.create! below) seems to cause NoMethodErrors. Example with stack trace below, I tried it on mongoid master, seems to also happen on mongoid rc7.

<pre>
class Tag
include Mongoid::Document
field :name, :type => String

validates :name, :format => {:with => /^[a-z -]+$/}
end
</pre>

<pre>
ruby-1.9.2-p136 :003 > Tag.safely.create!
NoMethodError: undefined method `merge' for #<Tag _id: 4d6705aa19418f42b4000003, name: nil>
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/attributes.rb:199:in `method_missing'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/safety.rb:173:in `method_missing'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/safety.rb:94:in `block in create!'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/safety.rb:93:in `tap'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/safety.rb:93:in `create!'
from (irb):3
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands/console.rb:44:in `start'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands/console.rb:8:in `start'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands.rb:23:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
</pre>
expected behavior:
<pre>
ruby-1.9.2-p136 :002 > Tag.create!
Mongoid::Errors::Validations: Validation failed - Name is invalid.
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/persistence.rb:234:in `fail_validate!'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/mongoid-2.0.0.rc.7/lib/mongoid/persistence.rb:182:in `create!'
from (irb):2
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands/console.rb:44:in `start'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands/console.rb:8:in `start'
from /home/mark/.rvm/gems/ruby-1.9.2-p136/gems/railties-3.0.4/lib/rails/commands.rb:23:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
</pre>