env() breaks libsass

[danwood]

Libsass doesn’t understand the new “env” that Apple has introduced into the syntax.

/* Use @supports per https://webkit.org/blog/7929/designing-websites-for-iphone-x/ */
@supports(padding: max(0px)) {
    .post {
        padding-left: max(1em, env(safe-area-inset-left));
        padding-right: max(1em, env(safe-area-inset-right));
    }
}

Actual results

Libsass: Error: "env(safe-area-inset-left)" is not a number for `max'
      on line 231 of /path/to/css/main.scss
      padding-left: max(1em, env(safe-area-inset-left));
 ----------------------^

Expected result

There should be no error.

version info:

Sass 3.5.1 (Bleeding Edge)

[mgreter]

IMO this is also not supported by ruby sass, tested with Sass 3.5.5 (Bleeding Edge).

Error: "env(safe-area-inset-left)" is not a number for `max'

[mgreter]

This should probably be reported upstream //CC @nex3 @chriseppstein

[nex3]

This is a duplicate of sass/sass#2378. The issue here isn't really env(), it's that CSS introduced max() and min() functions that work very differently than the existing Sass functions with the same names.