Errors on old filter: alpha() function

[danny-andrews]

I'm getting an error when trying to run postcss-env-fn on some code which uses the old syntax for applying opacity (filter: alpha(opacity=23)).

Code:

.className {
  filter: alpha(opacity=45);
}

Error message:

CssSyntaxError: postcss-env-fn: <css input>:1:1: Unknown word

[jonathantneal]

I’m not sure what this is. You are not using the env() function in this code. Feel free to hit me back up if there is something we can use to reproduce the issue using this plugin.