Can't save nested model on polymorphic association - ruby-on-rails

Question

Forced to ask for help with saving nested models on polymorphic association. I'm missing something but can't figure out what.
Everithing pretty straightforward. There is Address which can have multiple Phones.
So models are
class Address < ActiveRecord::Base
has_many :phones, as: :phoneable
accepts_nested_attributes_for :phones, allow_destroy: true
validates :city, :street, :building, :name, presence: true
end
and
class Phone < ActiveRecord::Base
belongs_to :phoneable, polymorphic: true
validates :number, :extension, presence: true
end
addresses_controller.rb
def new
#address = Address.new
#phone = #address.phones.build
authorize #address
end
def create
#address = Address.create(address_params)
authorize #address
if #address.save
binding.pry
flash[:success] = "Address #{#address.name} created"
redirect_to address_path(#address)
else
flash.now[:danger] = 'Failed'
render :new
end
end
def address_params
params.require(:address).permit(:name, :street, :building, :city, phones_attributes: [:id, :number, :extension, :details] )
end
/app/views/address.html.erb
<div class="row">
<div class="col-md-12">
<%= form_for(#address, html: {class: 'form-horizontal', role: 'form'}) do |f| %>
<%= render 'shared/errors', obj: #address, model_name: 'addresses' %>
<div id="create-form">
<div class="form-group">
<div class="control-label col-md-4">
<%= f.label :city, 'Город' %>
</div>
<div class="col-md-4">
<%= f.select(:city, options_for_select(['Moscow', 'Samara']), {}, {class: "form-control"}) %>
</div>
</div>
<div class="form-group">
<div class="control-label col-md-4">
<%= f.label :street, 'Street' %>
</div>
<div class="col-md-4">
<%= f.text_field :street, class: 'form-control' %>
</div>
</div>
<div class="form-group">
<div class="control-label col-md-4">
<%= f.label :building, 'Building' %>
</div>
<div class="col-md-4">
<%= f.text_field :building, class: 'form-control' %>
</div>
</div>
<div class="form-group">
<div class="control-label col-md-4">
<%= f.label :name, 'Place name' %>
</div>
<div class="col-md-4">
<%= f.text_field :name, class: 'form-control' %>
</div>
</div>
<div class="form-group">
<div class="control-label col-md-4">
<%= f.label :phones, 'Phone' %>
</div>
<div class="col-md-4">
<%= f.fields_for :phone do |phone_form| %>
<%= phone_form.text_field :number, class: 'form-control' %>
</div>
</div>
<div class="form-group">
<div class="control-label col-md-4">
<%= phone_form.label :extension, 'Ext.' %>
</div>
<div class="col-md-4">
<%= phone_form.text_field :extension, class: 'form-control' %>
</div>
<% end %>
</div>
<div class="form-group">
<div class='col-md-offset-4 col-md-6'>
<%= f.submit #address.new_record? ? 'Add' : 'Update', class: 'btn btn-primary btn-md' %>
</div>
</div>
</div>
<% end %>
</div>
</div>
First issue I encountered with is if I set key :phones instead :phone into the following line <%= f.fields_for :phone do |phone_form| %> my phone text fields don't render in view but they should. One user emphasized this moment here https://stackoverflow.com/a/3328041/2049476
if I use :phone everything somehow works fine but seems like it's wrong.
And the second one.
Phone object doesn't save in DB, when I create new address or edit current I succeed but phone doesn't show any validation errors if I leave all it fields blank.
Here what I have in params hash
{"utf8"=>"✓",
"authenticity_token"=>"inwXr3Ev/Aj/hZRY2IadizDHDgdSFo2zFhY9DAvysfFu3jjD9AS66esKVsTzEuKo2WC46YQt6HnOKTgInvfUEg==",
"address"=>{"city"=>"Moscow", "street"=>"ul. Tsentralnaya d. 4 kv. 220", "building"=>"1212", "name"=>"Astoria", "phone"=>{"number"=>"9215555555", "extension"=>"111"}},
"commit"=>"Add",
"controller"=>"addresses",
"action"=>"create"}
What am I missing?

Answer 1

Try answer for 2 issues:
The correct way is to pass :phones, and then phone as variable to field_for, like is was done here:
<%- #address.phones.each.with_index do |phone, index| %>
<%- f.fields_for :phones, phone do |phone_form| %>
<%- end %>
<%- end %>
Should be resolved as of the 1-st question, since the fields shoudl sent ot server via params not a phone hash, but phones_attributes array of hashes, in order to accepts_nested_attributes_for could accept phones:
phones_attributes: [{ ... },{ ... }]