@layer declarations not found when using grouped selectors

[ndimatteo]

What version of Tailwind CSS are you using?
v3.0.9

What build tool (or framework if it abstracts the build tool) are you using?
postcss ^8.3.11, Next.js ^12.0.4

What version of Node.js are you using?
v14.0.0

What browser are you using?
Chrome

What operating system are you using?
macOS

Reproduction URL
https://play.tailwindcss.com/EdpBQBdhBF?file=css

Describe your issue
Hey there! You used to be able to group selectors in an @layer declaration, but now it's throwing an error.

In the reproduction URL try removing the h1, selector and it will work again 😃

[RobinMalfait]

Hey! Thank you for your bug report!
Much appreciated! 🙏

This was indeed working in the older AOT mode, but never worked in JIT mode.

This should be fixed in #6922, and will be available in the next release (probably later today).

You can already try it by using the insiders build npm install tailwindcss@insiders or yarn add tailwindcss@insiders.