False positive + bad autocorrect for Rails/Pluck

[jcoyne]

I had this line of code:

      label_value = facet_config.pivot.map(&:to_sym).map { |k| item_fq[k] }

and when I ran rubocop it complained:

Inspecting 1 file
C

Offenses:

app/presenters/blacklight/facet_item_pivot_presenter.rb:27:56: C: [Corrected] Rails/Pluck: Prefer pluck(k) over map { |k| item_fq[k] }.
        label_value = facet_config.pivot.map(&:to_sym).map { |k| item_fq[k] }
                                                       ^^^^^^^^^^^^^^^^^^^^^^

and it was autocorrected to

        label_value = facet_config.pivot.map(&:to_sym).pluck(k)

This new code is broken as k is not defined.

Rubocop version 1.37.1
rubocop-rails version 2.17.1

[jcoyne]

Here's another example of a bad autocorrect it did:

items.map {|_facet, opts| opts[:group] }

items.pluck(:group)

Now consider that items is:

items = { a: { group: 1}}

it results in:

no implicit conversion of Symbol into Integer (TypeError)

[vlad-pisanov]

This is same as #833 -- the fix is on master 🙌