Lint/EmptyConditionalBody cop throws an error when inspecting a conditional with multiple empty branches

[davidenglishmusic]

The cop throws an error when inspecting a conditional with more than one empty branch.

---

Expected behavior

It should not throw an error.

Actual behavior

It throws an error.

An error occurred while Lint/EmptyConditionalBody cop was inspecting /Users/david/code/rubocop-test/app.rb:7:0.
undefined method `line' for nil:NilClass
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/mixin/comments_help.rb:55:in `find_end_line'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/mixin/comments_help.rb:16:in `contains_comments?'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/lint/empty_conditional_body.rb:62:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:100:in `public_send'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:100:in `block (2 levels) in trigger_responding_cops'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:160:in `with_cop_error_handling'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:99:in `block in trigger_responding_cops'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:98:in `each'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:98:in `trigger_responding_cops'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:69:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-ast-1.16.0/lib/rubocop/ast/traversal.rb:156:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:71:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-ast-1.16.0/lib/rubocop/ast/traversal.rb:156:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:71:in `on_if'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-ast-1.16.0/lib/rubocop/ast/traversal.rb:20:in `walk'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/commissioner.rb:86:in `investigate'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/team.rb:155:in `investigate_partial'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cop/team.rb:83:in `investigate'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:309:in `inspect_file'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:253:in `block in do_inspection_loop'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:287:in `block in iterate_until_no_changes'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:280:in `loop'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:280:in `iterate_until_no_changes'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:249:in `do_inspection_loop'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:130:in `block in file_offenses'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:155:in `file_offense_cache'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:129:in `file_offenses'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:67:in `block in warm_cache'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:587:in `call_with_index'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:557:in `process_incoming_jobs'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:537:in `block in worker'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:528:in `fork'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:528:in `worker'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:519:in `block in create_workers'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `each'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `each_with_index'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:518:in `create_workers'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:457:in `work_in_processes'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:294:in `map'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/parallel-1.22.1/lib/parallel.rb:238:in `each'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:67:in `warm_cache'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/runner.rb:46:in `run'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/command/execute_runner.rb:26:in `block in execute_runner'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/command/execute_runner.rb:52:in `with_redirect'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/command/execute_runner.rb:25:in `execute_runner'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/command/execute_runner.rb:17:in `run'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/command.rb:11:in `run'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli/environment.rb:18:in `run'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli.rb:71:in `run_command'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli.rb:78:in `execute_runners'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/lib/rubocop/cli.rb:47:in `run'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/exe/rubocop:12:in `block in <top (required)>'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/2.6.0/benchmark.rb:308:in `realtime'
/Users/david/.rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/rubocop-1.27.0/exe/rubocop:12:in `<top (required)>'
/Users/david/.rbenv/versions/2.6.6/bin/rubocop:23:in `load'
/Users/david/.rbenv/versions/2.6.6/bin/rubocop:23:in `<main>'

Steps to reproduce the problem

Create app.rb with the following code:

# frozen_string_literal: true

if condition_a
  puts 'hello'
elsif condition_b
  # Do nothing
elsif condition_c
  # Do nothing
end

Run rubocop app.rb

RuboCop version

% rubocop -V     
1.27.0 (using Parser 3.1.1.0, rubocop-ast 1.16.0, running on ruby 2.6.6 -darwin20)