Error: Base-level rules cannot contain the parent-selector-referencing character '&'.
        on line 30 of /sass/spec/libsass-issues/issue_1644/complex/input.scss, in `@content'
        from line 22 of /sass/spec/libsass-issues/issue_1644/complex/input.scss, in `grid-media-query'
        from line 29 of /sass/spec/libsass-issues/issue_1644/complex/input.scss
  Use --trace for backtrace.
