fails:Regexps with interpolation allows interpolation of literal regexps
fails:Regexps with interpolation allows interpolation of any class that responds to to_s
fails:Regexps with interpolation allows interpolation which mixes modifiers
fails:Regexps with interpolation gives precedence to escape sequences over substitution
fails:Regexps with interpolation throws RegexpError for malformed interpolation
fails:Regexps with interpolation allows interpolation in extended mode
fails:Regexps with interpolation allows escape sequences in interpolated regexps
