<===> input.scss
$GLOBAL: global;

@function foo($g1, $g2, $g3) {
  @each $value in $g1, $g2, $g3 {
    $GLOBAL: $GLOBAL each $value !global;
    $GLOBAL: $GLOBAL type1 type-of(nth($value, 1)) !global;
    $GLOBAL: $GLOBAL type2 type-of(nth($value, 2)) !global;
  }
  @each $value in (foo: foo, bar: bar) {
    $GLOBAL: $GLOBAL map $value !global;
  }
  @return 0;
}

div {
  a: foo(50% 50%, cover circle, red blue);
  b: $GLOBAL;
  $colors: red green blue;
  c: a, b, type-of(nth($colors, 2)), d;
}

<===> output.css
div {
  a: 0;
  b: global each 50% 50% type1 number type2 number each cover circle type1 string type2 string each red blue type1 color type2 color map foo foo map bar bar;
  c: a, b, color, d;
}