Error in Style/IfUnlessModifier cop when using .(attr:) (implicit call method)

[pdobb]

There's an error being produced by Style/IfUnlessModifier cop when inspecting code such as this:

if some_condition?
  my_callable.(attr:)
end

It doesn't fail if I either:

1. Use call explicitly: my_callable.call(attr:), or
2. Remove all arguments: my_callable.()

---

Expected behavior

Shouldn't get an error from Style/IfUnlessModifier cop in either case.

Actual behavior

Error is raised:

Here, I used the default config by just modifying TargetRubyVersion: ~ -> TargetRubyVersion: 3.3. I didn't see a way to specify target ruby version on the rubocop command line.

$ rubocop -d --config=/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/config/default.yml rubocop.rb
configuration from /Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/config/default.yml
Default configuration from /Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/config/default.yml
Use parallel by default.
Skipping parallel inspection: only a single file needs inspection
Inspecting 1 file
Scanning /Users/paul/dev/rubocop.rb
An error occurred while Style/IfUnlessModifier cop was inspecting /Users/paul/dev/rubocop.rb:1:0.
undefined method `end_pos' for nil
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:68:in `method_source'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:61:in `if_body_source'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:52:in `to_modifier_form'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:47:in `length_in_modifier_form'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:41:in `modifier_fits_on_single_line?'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/mixin/statement_modifier.rb:17:in `single_line_as_modifier?'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/style/if_unless_modifier.rb:125:in `message'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/style/if_unless_modifier.rb:84:in `on_if'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:107:in `public_send'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:107:in `block (2 levels) in trigger_responding_cops'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:171:in `with_cop_error_handling'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:106:in `block in trigger_responding_cops'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:105:in `each'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:105:in `trigger_responding_cops'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:69:in `on_if'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-ast-1.32.3/lib/rubocop/ast/traversal.rb:20:in `walk'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/commissioner.rb:87:in `investigate'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/team.rb:168:in `investigate_partial'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cop/team.rb:102:in `investigate'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:349:in `block in inspect_file'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:348:in `each'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:348:in `flat_map'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:348:in `inspect_file'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:291:in `block in do_inspection_loop'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:325:in `block in iterate_until_no_changes'
<internal:kernel>:187:in `loop'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:318:in `iterate_until_no_changes'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:287:in `do_inspection_loop'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:168:in `block in file_offenses'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:193:in `file_offense_cache'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:167:in `file_offenses'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:158:in `process_file'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:139:in `block in each_inspected_file'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:138:in `each'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:138:in `reduce'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:138:in `each_inspected_file'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:124:in `inspect_files'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/runner.rb:77:in `run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/command/execute_runner.rb:26:in `block in execute_runner'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/command/execute_runner.rb:52:in `with_redirect'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/command/execute_runner.rb:25:in `execute_runner'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/command/execute_runner.rb:17:in `run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/command.rb:11:in `run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli/environment.rb:18:in `run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli.rb:122:in `run_command'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli.rb:129:in `execute_runners'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli.rb:51:in `block in run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli.rb:81:in `profile_if_needed'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/lib/rubocop/cli.rb:43:in `run'
/Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/exe/rubocop:19:in `<top (required)>'
/Users/paul/.gem/ruby/3.3.4/bin/rubocop:25:in `load'
/Users/paul/.gem/ruby/3.3.4/bin/rubocop:25:in `<main>'
C

Offenses:

rubocop.rb:1:1: C: [Correctable] Style/FrozenStringLiteralComment: Missing frozen string literal comment.
if some_condition?
^
rubocop.rb:2:3: C: [Correctable] Style/LambdaCall: Prefer the use of my_callable.call(attr:) over my_callable.(attr:).
  my_callable.(attr:)
  ^^^^^^^^^^^^^^^^^^^

1 file inspected, 2 offenses detected, 2 offenses autocorrectable

1 error occurred:
An error occurred while Style/IfUnlessModifier cop was inspecting /Users/paul/dev/rubocop.rb:1:0.
configuration from /Users/paul/.gem/ruby/3.3.4/gems/rubocop-1.66.1/config/default.yml
Errors are usually caused by RuboCop bugs.
Please, report your problems to RuboCop's issue tracker.
https://github.com/rubocop/rubocop/issues

Mention the following information in the issue report:
1.66.1 (using Parser 3.3.5.0, rubocop-ast 1.32.3, running on ruby 3.3.4) [arm64-darwin23]
Finished in 0.1894209999591112 seconds

Steps to reproduce the problem

# This reproduces the error
if some_condition?
  my_callable.(attr:)
end

# Works fine
if some_condition?
  my_callable.()
end

# Works fine
if some_condition?
  my_callable.call(attr:)
end

RuboCop version

rubocop -V
1.66.1 (using Parser 3.3.5.0, rubocop-ast 1.32.3, running on ruby 3.3.4) [arm64-darwin23]