Fix intellisense for plugins with multiple @apply rules (#8213)

* Fix intellisense for plugins with multiple `@apply` rules

Intellisense uses `expandApplyAtRules` directly and doesn’t partition them. When a plugin registers components using something like `”@apply flex”: {}` more than once in the same component intellisense will break. This isn’t a problem for Tailwind CSS proper because we do rule partitioning. Given that Intellisense is using it directly though we shouldn’t outright break in the face of this situation even if the result isn’t 100% accurate (the source maps won’t be correct in this case).

* Update changelog

Co-authored-by: psucoder <hungle.info@gmail.com>

CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Require matching prefix when detecting negatives ([#8121](https://github.com/tailwindlabs/tailwindcss/pull/8121))
 - Handle duplicate At Rules without children ([#8122](https://github.com/tailwindlabs/tailwindcss/pull/8122))
 - Allow arbitrary values with commas in `@apply` ([#8125](https://github.com/tailwindlabs/tailwindcss/pull/8125))
+- Fix intellisense for plugins with multiple `@apply` rules ([#8213](https://github.com/tailwindlabs/tailwindcss/pull/8213))
 
 ### Added
 

src/lib/expandApplyAtRules.js

@@ -309,7 +309,7 @@ function processApply(root, context, localCache) {
 
   // Collect all apply candidates and their rules
   for (let apply of applies) {
-    let candidates = []
+    let [candidates] = perParentApplies.get(apply.parent) || [[], apply.source]
 
     perParentApplies.set(apply.parent, [candidates, apply.source])