Detect delegate to self

[andyw8]

I discovered some code like this:

delegate :foo, to: self

foo is a class method. So calling foo in an instance method would be equivalent to self.class.foo.

I can't see how this confusing indirection would ever make sense. If a method needs to be available as both an instance and a class method, then there's probably a problem in the design.

Any thoughts? Should rubocop-rails detect this?

[andyw8]

To check how common this is, I grepped the set of apps from real-world-rails and only found a handful of occurrences:

discourse/app/models/category.rb
110:  delegate :post_template, to: 'self.class'

e-petitions/app/models/constituency.rb
17:  delegate :query, :example_postcodes, to: "self.class"

foreman/app/models/compute_resources/foreman/model/ec2.rb
7:    delegate :security_groups, :flavors, :zones, :to => :self, :prefix => 'available'

foreman/app/models/subnet.rb
104:  delegate :supports_ipam_mode?, :supported_ipam_modes, :show_mask?, to: 'self.class'

solidus/core/app/models/spree/promotion_code/batch_builder.rb
24:    delegate attr, to: self