Dart Sass - Partial not included in Source Map

@use "sass:math";

$base: 16px !default;

@function strip-unit($number) {
    @if unitless($number) {
        @return $number;
    }
    @return math.div($number, $number * 0 + 1);
}

@function to-em($px, $base-context: $base) {
    $val: strip-unit($px);
    $base-val: strip-unit($base-context);
    @return ($val / $base-val) * 1em;
}

@use "functions";

html {
  height: functions.to-em(768px);
}