Nested CSS adds extra & characters (that are not necessary?)

[KeesCBakker]

It looks like nested css adds extra & characters, which are not needed. I'm using NPM version 1.28.2 of the lightningcss package.

const { transform } = require("lightningcss");

let css = `
.outer {
  color: red;
  .inner {
    color: blue;
  }
  .another-inner {
    color: black;
  }
}`;

let { code } = transform({
  code: Buffer.from(css),
  minify: true,
  sourceMap: false
});

console.log(code.toString());

This outputs:

.outer{color:red;& .inner{color:#00f}& .another-inner{color:#000}}

When I prettify it, we'll get:

.outer {
	color: red;

	& .inner {
		color: #00f
	}

	& .another-inner {
		color: #000
	}
}

Why are the &-characters added? I think they might not be needed.

[fregante]

It used to be required, refer to "Partial support" notes on https://issues.chromium.org/40261706 or the specific Chromium issue https://issues.chromium.org/issues/40261706