Layout/MultilineMethodCallIndentation reports false positives if using Ruby 2.7 numbered parameters

[DMA57361]

Expected behavior

Code that correctly confirms to the Layout/MultilineMethodCallIndentation cop's default "aligned" enforced style while making use of blocks with Ruby 2.7's new numbered parameters feature should not raise an offense.

Actual behavior

Lines that follow the numbered parameter block are reported as being indented incorrectly.

Steps to reproduce the problem

Given the following example.rb file:

File.read('data.yml')
    .then { |file| YAML.safe_load file } # normal block param
    .transform_values(&:downcase)
    .freeze

File.read('data.yml')
    .then { YAML.safe_load _1 } # numbered param
    .transform_values(&:downcase)
    .freeze

Running rubocop cop gives the following results:

$ rubocop example.rb --only Layout/MultilineMethodCallIndentation
Inspecting 1 file
C

Offenses:

example.rb:8:5: C: Layout/MultilineMethodCallIndentation: Use 2 (not 4) spaces for indenting an expression spanning multiple lines.
    .transform_values(&:downcase)
    ^^^^^^^^^^^^^^^^^
example.rb:9:5: C: Layout/MultilineMethodCallIndentation: Use 2 (not 4) spaces for indenting an expression spanning multiple lines.
    .freeze
    ^^^^^^^

1 file inspected, 2 offenses detected

Note how the first version of the code in the file (using normal block params) is considered correct while the second version (using Ruby 2.7 numbered params) is considered incorrect.

RuboCop version

$ bundle exec rubocop -V
0.80.1 (using Parser 2.7.0.4, running on ruby 2.7.0 x86_64-linux)