class RuboCop::Cop::Style::StringLiteralsInInterpolation

def message(*)
  # single_quotes -> single-quoted
  kind = style.to_s.sub(/_(.*)s/, '-\1d')
  "Prefer #{kind} strings inside interpolations."
end

def offense?(node)
  # If it's not a string within an interpolation, then it's not an
  # offense for this cop.
  return false unless inside_interpolation?(node)
  wrong_quotes?(node)
end