From eeba86d72149f76b3b35f6e316fa4a789974ef26 Mon Sep 17 00:00:00 2001
From: Daniel Puckowski <puckowski.d@gmail.com>
Date: Sat, 22 Nov 2025 17:21:30 -0500
Subject: [PATCH] fix(issue#4354): unknown at-rule expression commas

* Fix issue #4354 unknown at-rule expressions should not have commas in
  a keyword list.
* Add some additional layer at-rule tests.
---
 packages/less/src/less/tree/atrule.js       |  3 --
 packages/test-data/css/_main/layer.css      | 40 +++++++++++++++
 packages/test-data/css/_main/tailwind.css   |  3 ++
 packages/test-data/less/_main/layer.less    | 54 +++++++++++++++++++++
 packages/test-data/less/_main/tailwind.less |  3 ++
 5 files changed, 100 insertions(+), 3 deletions(-)
 create mode 100644 packages/test-data/css/_main/tailwind.css
 create mode 100644 packages/test-data/less/_main/tailwind.less

diff --git a/packages/less/src/less/tree/atrule.js b/packages/less/src/less/tree/atrule.js
index df36a5d87..15301f29b 100644
--- a/packages/less/src/less/tree/atrule.js
+++ b/packages/less/src/less/tree/atrule.js
@@ -135,9 +135,6 @@ AtRule.prototype = Object.assign(new Node(), {
 
         if (value) {
             value = value.eval(context);
-            if (value.value && this.keywordList(value.value)) {
-                value = new Anonymous(value.value.map(keyword => keyword.value).join(', '), this.getIndex(), this.fileInfo());
-            }
         }
 
         if (rules) {
diff --git a/packages/test-data/css/_main/layer.css b/packages/test-data/css/_main/layer.css
index 7196325af..31e54d2bb 100644
--- a/packages/test-data/css/_main/layer.css
+++ b/packages/test-data/css/_main/layer.css
@@ -91,3 +91,43 @@
     color: #555;
   }
 }
+@layer theme;
+@layer layout, utilities;
+body {
+  color: black;
+}
+@layer components {
+  .btn {
+    color: red;
+  }
+  .btn:hover {
+    color: blue;
+  }
+}
+@layer {
+  p {
+    margin-block: 1rem;
+  }
+}
+@layer framework.buttons.primary {
+  .btn-primary {
+    background: dodgerblue;
+    color: white;
+  }
+}
+.feature {
+  color: gray;
+}
+@layer component {
+  .feature h2 {
+    font-size: 1.5rem;
+  }
+}
+@layer ui {
+  .btn {
+    padding: 0.5rem 1rem;
+    border-radius: 4px;
+    background: rebeccapurple;
+    color: white;
+  }
+}
diff --git a/packages/test-data/css/_main/tailwind.css b/packages/test-data/css/_main/tailwind.css
new file mode 100644
index 000000000..499decb21
--- /dev/null
+++ b/packages/test-data/css/_main/tailwind.css
@@ -0,0 +1,3 @@
+.box {
+  @apply h-64 w-64;
+}
diff --git a/packages/test-data/less/_main/layer.less b/packages/test-data/less/_main/layer.less
index 9340f83af..4d16c00b8 100644
--- a/packages/test-data/less/_main/layer.less
+++ b/packages/test-data/less/_main/layer.less
@@ -110,3 +110,57 @@
         color: #555;
     }
 }
+
+@layer theme;
+@layer layout, utilities;
+
+body {
+  color: black;
+}
+
+@layer components {
+  .btn {
+    color: red;
+    &:hover {
+      color: blue;
+    }
+  }
+}
+
+@layer {
+  p {
+    margin-block: 1rem;
+  }
+}
+
+@layer framework.buttons.primary {
+  .btn-primary {
+    background: dodgerblue;
+    color: white;
+  }
+}
+
+.feature {
+  color: gray;
+
+  @layer component {
+    h2 {
+      font-size: 1.5rem;
+    }
+  }
+}
+
+@primary-color: rebeccapurple;
+
+.button-styles() {
+  padding: 0.5rem 1rem;
+  border-radius: 4px;
+}
+
+@layer ui {
+  .btn {
+    .button-styles();
+    background: @primary-color;
+    color: white;
+  }
+}
diff --git a/packages/test-data/less/_main/tailwind.less b/packages/test-data/less/_main/tailwind.less
new file mode 100644
index 000000000..499decb21
--- /dev/null
+++ b/packages/test-data/less/_main/tailwind.less
@@ -0,0 +1,3 @@
+.box {
+  @apply h-64 w-64;
+}