v5: shift-color() not working correctly with dark default link color?

Created by: marcelmoreau

If I want a dark color as my default link color (e.g. #111111), I would want its hover state to lighten the color instead of darkening it. It would appear that v5 accounts for this in its variables file, using the shift-color() function.

$link-color: $primary !default;
$link-decoration: underline !default;
$link-shade-percentage: 20% !default;
$link-hover-color: shift-color($link-color, $link-shade-percentage) !default;
$link-hover-decoration: null !default;

According to shift-color()’s comment , it should “Shade the color if the weight is positive, else tint it”. This sounds perfect and is exactly what I hope for. But if I pass a negative percentage like -20% to $link-shade-percentage in hopes of tinting it, I get a Sass compilation error: $weight: Expected -20% to be within 0% and 100%.

This aligns with that Sass says, that mix() only accepts 0% - 100% weight, but I don't know. Am I doing this wrong? Thanks for your work getting v5 out!