How to add class and additional property in mixin in stylus?

Question

css

There is a universal placeholder mixin for all browsers

placeholder-input(color)
  input[type='text']::-webkit-input-placeholder,
  input[type='email']::-webkit-input-placeholder,
  input[type='phone']::-webkit-input-placeholder
    color color
  /* webkit */

  input[type='text']::-moz-placeholder,
  input[type='email']::-moz-placeholder,
  input[type='phone']::-moz-placeholder
    color color

  /* webkit */

  input[type='text']:-moz-placeholder,
  input[type='email']:-moz-placeholder,
  input[type='phone']:-moz-placeholder
    color color

  /* webkit */

  input[type='text']:-ms-input-placeholder,
  input[type='email']:-ms-input-placeholder,
  input[type='phone']:-ms-input-placeholder
    color color

I had a problem when I need to change the color of the placeholder if the inputs have an error class.
I understand that you can set 2 more parameters, class and color2.
Only how to set empty parameters or by default?
I tried like this

placeholder-input(color, class false, color2 = false)
  input[type='text']::-webkit-input-placeholder,
  input[type='email']::-webkit-input-placeholder,
  input[type='phone']::-webkit-input-placeholder
    color color
    if class
      &.class = class
        color color2
  /* webkit */

Only for some reason in the browser styles are not applied?

Answer 1

as an example with nesting
https://codepen.io/anon/pen/Ezjppv