<===> input.scss
@function foo($list) {
    @return call(bar, $list);
}

@function bar($list, $args...) {
    @return length($list);
}

test {
  test: foo(1 2 3);
}

<===> output.css
test {
  test: 3;
}

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

  ,
2 |     @return call(bar, $list);
  |             ^^^^^^^^^^^^^^^^
  '
    input.scss 2:13  foo()
    input.scss 10:9  root stylesheet