Extending from custom class gives @@validators errors

[Thellior]

When creating an application_record.cr and extending it Granite::Base it works.
When i create an model user.cr and extend from application_record.cr it will raise an compiler error saying that @@Validators are already defined.

class ApplicationRecord < Granite::Base
  adapter pg
end

class User < ApplicationRecord
  # Table
  table_name users

  # Fields
  field username : String
  field password : String

  timestamps

  # Validations
  validate_not_blank :username
  validate_not_blank :password
  validate_uniqueness :username
end

Error in src/models/user.cr:1: expanding macro

class User < ApplicationRecord
^

in macro 'inherited' expanded macro: included:1, line 1:

>  1.       @@validators = Array({field: String, message: String, block: Proc(self, Bool)}).new
   2.
   3.       def self.validate(message : String, &block : self -> Bool)
   4.         self.validate(:base, message, block)
   5.       end
   6.
   7.       def self.validate(field : (Symbol | String), message : String, &block : self -> Bool)
   8.         self.validate(field, message, block)
   9.       end
  10.
  11.       def self.validate(message : String, block : self -> Bool)
  12.         self.validate(:base, message, block)
  13.       end
  14.
  15.       def self.validate(field : (Symbol | String), message : String, block : self -> Bool)
  16.         @@validators << {field: field.to_s, message: message, block: block}
  17.       end
  18.

class variable '@@validators' of User is already defined as Array(NamedTuple(field: String, message: String, block: Proc(ApplicationRecord, Bool))) in ApplicationRecord

[robacarp]

Yeah, right now this isn't supported on Granite.

The easiest way to accomplish what you're trying to do is with a module which you import into your models. I do this and it works reasonably well. I'm not sure it'll work with the adapter macro though.

[Blacksmoke16]

Duplicate of #123