Array of points error (Rails 6)

bug_array_of_points.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"
  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails"
  gem 'pg'
end

require "active_record"
require "minitest/autorun"
require "logger"

ActiveRecord::Base.establish_connection(adapter: 'postgresql', database: 'TODO', username: 'TODO', password: 'TODO')
ActiveRecord::Base.logger = Logger.new(STDOUT)



ActiveRecord::Schema.define do
  create_table :shapes, force: true do |t|
    t.column :centroid, :point
    t.column :polygon, :point, array: true
  end
end

class Shape < ActiveRecord::Base
end

class ArrayOfPointsTest < Minitest::Test
  def test_point # Succeeds!
    Shape.create!(centroid: [0.4, 0.7])
  end

  def test_array_of_points # Fails!
    Shape.create!(polygon: [[0.1, 0.2],
                            [0.3, 0.4],
                            [0.5, 0.6],
                            [0.7, 0.8],
                            [0.1, 0.2]])
  end
end