<===> input.scss
@function foo($this, $my) {
  @return (this: $this, my: $my);
}

a {
  $map: foo((this: is, my: map)...);
  @each $k, $v in $map {
    #{$k}: $v;
  }
}

b {
  $map: call("foo", (this: is, my: map)...);
  @each $k, $v in $map {
    #{$k}: $v;
  }
}

<===> output.css
a {
  this: is;
  my: map;
}

b {
  this: is;
  my: map;
}

<===> warning
DEPRECATION WARNING: Passing a string to call() is deprecated and will be illegal
in Sass 4.0. Use call(function-reference(foo)) instead.

<===> warning-dart-sass
DEPRECATION WARNING: Passing a string to call() is deprecated and will be illegal
in Dart Sass 2.0.0. Use call(get-function("foo")) instead.

   ,
13 |   $map: call("foo", (this: is, my: map)...);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   '
    input.scss 13:9  root stylesheet