Class ActiveRecord::AssociationTypeMismatch
In: vendor/rails/activerecord/lib/active_record/base.rb
Parent: ActiveRecordError

Raised when object assigned to association is of incorrect type.

Example:

class Ticket < ActiveRecord::Base

  has_many :patches

end

class Patch < ActiveRecord::Base

  belongs_to :ticket

end

and somewhere in the code:

@ticket.patches << Comment.new(:content => "Please attach tests to your patch.") @ticket.save

[Validate]