Which @angular/* package(s) are the source of the bug?

compiler

Is this a regression?

Yes

Description

The following code used to work in 18.2.7

:host {
  &:not(&.foo, &.bar) {
    color: red;
  }
}

According to CSS Selectors 4 it is valid to put multiple selectors into one :not. With 18.2.8 we would need to chain two :nots together to get the same effect (&:not(&.foo):not(&.bar)). This somehow only seems to break on the host element.

Here is a reproduction with 18.2.8: https://stackblitz.com/edit/stackblitz-starters-3tx6cc?file=src%2Fmain.ts

Here is the same code with 18.2.7 where the first text has the expected color: https://stackblitz.com/edit/stackblitz-starters-oq4g3j?file=src%2Fmain.ts

Both have "inlineStyleLanguage": "scss" set (although that somehow doesn't seem to make a difference).

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 18.2.8
Node: 20.18.0
Package Manager: npm 10.9.0
OS: darwin arm64

Angular: 18.2.8
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, platform-browser, platform-browser-dynamic, router

Package Version

@angular-devkit/architect 0.1802.8
@angular-devkit/build-angular 18.2.8
@angular-devkit/core 18.2.8
@angular-devkit/schematics 18.2.8
@schematics/angular 18.2.8
ng-packagr 18.2.1
rxjs 7.8.1
typescript 5.5.4
zone.js 0.14.10