[Fix #551] Fix a false positive for Rails/FindEach

[koic]

Fixes #551.

This PR fixes a false positive for Rails/FindEach when using model.errors.where in Rails 6.1.

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.

[agrobbin]

This has resulted in a send_type? exception for us when trying to upgrade.

undefined method `send_type?' for nil:NilClass
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-rails-2.12.3/lib/rubocop/cop/rails/find_each.rb:58:in `active_model_error?'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-rails-2.12.3/lib/rubocop/cop/rails/find_each.rb:54:in `active_model_error_where?'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-rails-2.12.3/lib/rubocop/cop/rails/find_each.rb:46:in `ignored?'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-rails-2.12.3/lib/rubocop/cop/rails/find_each.rb:35:in `on_send'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:136:in `public_send'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:136:in `block (2 levels) in trigger_restricted_cops'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:160:in `with_cop_error_handling'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:135:in `block in trigger_restricted_cops'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:134:in `each'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:134:in `trigger_restricted_cops'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:70:in `on_send'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:158:in `on_block'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:71:in `on_block'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:137:in `block in on_dstr'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:137:in `each'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:137:in `on_dstr'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:71:in `on_begin'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:154:in `on_class'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:71:in `on_class'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:154:in `on_class'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:71:in `on_class'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:138:in `on_while'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:71:in `on_module'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-ast-1.12.0/lib/rubocop/ast/traversal.rb:20:in `walk'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/commissioner.rb:86:in `investigate'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/team.rb:155:in `investigate_partial'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cop/team.rb:83:in `investigate'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:309:in `inspect_file'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:253:in `block in do_inspection_loop'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:287:in `block in iterate_until_no_changes'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:280:in `loop'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:280:in `iterate_until_no_changes'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:249:in `do_inspection_loop'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:130:in `block in file_offenses'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:155:in `file_offense_cache'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:129:in `file_offenses'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:67:in `block in warm_cache'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:515:in `call_with_index'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:485:in `process_incoming_jobs'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:465:in `block in worker'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:456:in `fork'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:456:in `worker'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:447:in `block in create_workers'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:446:in `each'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:446:in `each_with_index'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:446:in `create_workers'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:386:in `work_in_processes'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:289:in `map'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/parallel-1.21.0/lib/parallel.rb:238:in `each'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:67:in `warm_cache'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/runner.rb:46:in `run'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/command/execute_runner.rb:26:in `block in execute_runner'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/command/execute_runner.rb:52:in `with_redirect'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/command/execute_runner.rb:25:in `execute_runner'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/command/execute_runner.rb:17:in `run'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/command.rb:11:in `run'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli/environment.rb:18:in `run'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli.rb:71:in `run_command'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli.rb:78:in `execute_runners'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/lib/rubocop/cli.rb:47:in `run'
/usr/local/var/rbenv/versions/3.0.2/lib/ruby/gems/3.0.0/gems/rubocop-1.22.1/exe/rubocop:12:in `block in <top (required)>'

The code in question looks like this:

where(record: [record1, record2]).each(&:touch)

Previously, we had been explicitly disabling Rails/FindEach on this line, but with this change, it also complains about an unnecessary disabling of the cop, which surprises us.

[koic]

@agrobbin Thanks for your feedback. I can reproduce the error and I fixed it by #573.