ieOpacityHack not working with `postcss-nested`

[Semigradsky]

Input:

td.options {
  text-align: center;

  .link {
    opacity: 0;
  }
}

Error:

ERROR in ./~/css-loader!./~/postcss-loader!./src/scripts/components/users/users.css Module build failed: TypeError: Cannot read property 'replace' of undefined at ieOpacityHack (D:\Dev\git\React\react-admin-example\node_modules\cssgrace\lib\index.js:270:31) at D:\Dev\git\React\react-admin-example\node_modules\cssgrace\lib\index.js:472:5

[viperfx07]

this happens to display: inline-block as well