Cop idea: Hash#values_at

[ydakuka]

Description

Use Hash#values_at or Hash#fetch_values when you need to retrieve several values consecutively from a hash.

https://rubystyle.guide/#hash-values-at-and-hash-fetch-values

Behavior

# bad
email = data['email']
username = data['nickname']

# bad
keys = %w[email nickname].freeze
email, username = keys.map { |key| data[key] }

# good
email, username = data.values_at('email', 'nickname')

# good
keys = %w[email nickname].freeze
email, username = data.values_at(*keys)

[ydakuka]

I am not sure that this rule does not conflict with the Style/ParallelAssignment cop.

[koic]

I am not sure that this rule does not conflict with the Style/ParallelAssignment cop.

Good point. It may be beneficial to re-review the https://rubystyle.guide/#hash-values-at rule in the style guide again before suggesting the cop implementation. Actually, it conflicts with the https://rubystyle.guide/#parallel-assignment rule as well.

[ydakuka]

Done. rubocop/ruby-style-guide#936