class RuboCop::Cop::Lint::Syntax

into RuboCop’s offenses.
This cop repacks Parser’s diagnostics/errors

def add_offense_from_diagnostic(diagnostic, ruby_version)

def add_offense_from_diagnostic(diagnostic, ruby_version)
  message =
    "#{diagnostic.message}\n(Using Ruby #{ruby_version} parser; " \
    'configure using `TargetRubyVersion` parameter, under `AllCops`)'
  add_offense(diagnostic.location,
              message: message,
              severity: diagnostic.level)
end

def add_offense_from_error(error)

def add_offense_from_error(error)
  message = beautify_message(error.message)
  add_global_offense(message, severity: :fatal)
end

def beautify_message(message)

def beautify_message(message)
  message = message.capitalize
  message << '.' unless message.end_with?('.')
  message
end

def on_other_file

def on_other_file
  add_offense_from_error(processed_source.parser_error) if processed_source.parser_error
  processed_source.diagnostics.each do |diagnostic|
    add_offense_from_diagnostic(diagnostic,
                                processed_source.ruby_version)
  end
  super
end