Cop idea: redundant FactoryBot enum traits

[pirj]

FactoryBot has an enum traits feature that given a model:

class Task < ActiveRecord::Base
  enum status: {queued: 0, started: 1, finished: 2}
end

makes the following definitions redundant:

FactoryBot.define do
  factory :task do
    trait :queued do
      status { :queued }
    end

It's near impossible to detect using static analysis, however, I've seen this defined as:

status { Model.status[:queued] }

which is equivalent to the above (just translates a symbol to its DB-level numeric representation explicitly rather than relying on ORM to do that). Those cases are detectable.

NOTE: Enum traits appeared in FactoryBot 6.1, so probably we'll need to introduce version configuration a-la TargetFactoryBotVersion (see rubocop-rails for an example).