DEPRECATION WARNING: Passing a string to call() is deprecated and will be illegal
in Sass 4.0. Use call(get-function(missing)) instead.

  foo: call(missing, 1px / 2px, 1px / round(1.5));
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    spec/libsass-issues/issue_1417/input.scss 10:8  root stylesheet
