Angular 21 cannot automatically recover using @apply with Tailwind CSS 4

[micobarac]

#17295

This hasn't been fixed. Angular 21.0.8 and Tailwind CSS 4.1.18.

Try setting invalid class value inside css file using @apply inset-shadow-md;:

Error: Cannot apply unknown utility class `inset-shadow-md`
    at onInvalidCandidate (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:21:1511)
    at Te (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:16:36652)
    at /Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:21:355
    at Rr (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:3:1718)
    at _ (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:3:1377)
    at $e (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:21:172)
    at un (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:38:294)
    at async cn (/Users/milan/Sites/tailwind-shader/node_modules/tailwindcss/dist/lib.js:38:631)
    at async Xr (/Users/milan/Sites/tailwind-shader/node_modules/@tailwindcss/node/dist/index.js:10:3417)
    at async I (/Users/milan/Sites/tailwind-shader/node_modules/@tailwindcss/postcss/dist/index.js:10:3977)
Application bundle generation failed. [0.046 seconds] - 2026-01-16T08:56:24.924Z

✘ [ERROR] Cannot apply unknown utility class `inset-shadow-md` [plugin angular-css]

Correcting error and setting class to a valid value, like @apply inset-shadow-sm;, application cannot recover until restart.

[beanscg]

Bean Labs took a public-source pass on this issue.

The narrowest useful next step looks like: identify compiler recovery boundary

Public evidence checked:

• tailwindcss/dist/lib.js

A good acceptance check would be a narrow public change that directly exercises the issue's reported boundary.

No PR opened from this pass.