If statement with color function fails with inherit value

[VovanR]

Example: https://codepen.io/VovanR/pen/qvJEeW?editors=1100

._btn(@color) {
  color: if((iscolor(@color)), darken(@color, 10%), @color);
  background-color: if((iscolor(@color)), green, pink);
}

.btn1 {
  ._btn(yellow);
}

.btn2 {
  ._btn(inherit);
}

body {
  color: lime;
}

I try to use iskeyword but it fails too

._btn(@color) {
  color: if((iskeyword(@color)), @color, darken(@color, 10%));
  background-color: if((iskeyword(@color)), pink, green);
}

But without color function in If statement it works fine. Try to comment color rule line

[seven-phases-max]

See #3371

[seven-phases-max]

Closing in favour of #3371.