scope with enum symbol causing `undefined method `[]' for nil:NilClass`

[denmarkmeralpis]

# foo.rb
class Foo < ApplicationRecord
  enum day: [:sunday, :monday, :tuesday, :wednesday, :thursday, :friday, :saturday]

  validates :start_time, :end_time, overlap: {
    scope: [:day, :another_column]
  }
end

Here's what I got when validation fails:

undefined method `[]' for nil:NilClass
Extracted source (around line #184):

#182 
#183       if is_enum_attribute?(record, attr_name)
*184         value = record.class.defined_enums[attr_name][value]
#185       end
#186 
#187       value
...

I think you need to cast the attr_name to string something like this attr_name.to_s

https://github.com/robinbortlik/validates_overlap/blob/4c2c837663379430e2605f9e66424d0a6e987f3f/lib/validates_overlap/overlap_validator.rb#L185