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

@function bar($predicate) {
  @return type-of($predicate);
}

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

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

<===> 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', $predicate);
  |           ^^^^^^^^^^^^^^^^^^^^^^^
  '
    input.scss 2:11  foo()
    input.scss 10:9  root stylesheet