class RuboCop::Cop::Lint::RegexpAsCondition

end
do_something
if /foo/ =~ $_
# good
end
do_something
if /foo/
# bad
@example
If a regexp literal is in condition, the regexp matches ‘$_` implicitly.
Checks for regexp literals used as `match-current-line`.

def on_match_current_line(node) 

def on_match_current_line(node)
  return if node.ancestors.none?(&:conditional?)
  return if part_of_ignored_node?(node)
  add_offense(node) { |corrector| corrector.replace(node, "#{node.source} =~ $_") }
  ignore_node(node)
end