set-nth and arglists don't play well together

[KittyGiraudel]

Test

@function double($value) {
  @return $value * 2;
}

@mixin dummy-bug($args...) {
  @for $i from 1 through length($args) {
    $args: set-nth($args, $i, double(nth($args, $i)));
  }

  content: $args;
}

.foo {
  @include dummy(1, 2, 3, 4);
}

Expected

.foo {
  content: 2, 4, 6, 8;
}

Result (LibSass 3.2.x)

Compile never ends.

Workaround

@mixin dummy($args...) {
  $list: ();

  @each $arg in $args {
    $list: append($list, double($arg), 'comma');
  }

  content: $list;
}

Observations

As far as I can tell, there is somehow an issue when trying to use set-nth on an arglist. Maybe is it only restricted when using a loop? I must say I don't know.

[xzyfer]

This may have the same underlying cause as #1171

[xzyfer]

Fixed by #1318.