Fixes less#3368

packages/less/src/less/functions/list.js

@@ -1,4 +1,5 @@
 import Comment from '../tree/comment';
+import Node from '../tree/node';
 import Dimension from '../tree/dimension';
 import Declaration from '../tree/declaration';
 import Expression from '../tree/expression';
@@ -65,20 +66,27 @@ export default {
         let newRules;
         let iterator;
 
+        const tryEval = val => {
+            if (val instanceof Node) {
+                return val.eval(this.context);
+            }
+            return val;
+        };
+
         if (list.value && !(list instanceof Quote)) {
             if (Array.isArray(list.value)) {
-                iterator = list.value;
+                iterator = list.value.map(tryEval);
             } else {
-                iterator = [list.value];
+                iterator = [tryEval(list.value)];
             }
         } else if (list.ruleset) {
-            iterator = list.ruleset.rules;
+            iterator = tryEval(list.ruleset).rules;
         } else if (list.rules) {
-            iterator = list.rules;
+            iterator = list.rules.map(tryEval);
         } else if (Array.isArray(list)) {
-            iterator = list;
+            iterator = list.map(tryEval);
         } else {
-            iterator = [list];
+            iterator = [tryEval(list)];
         }
 
         let valueName = '@value';

packages/test-data/css/namespacing/namespacing-8.css

@@ -0,0 +1,10 @@
+:root {
+  --background-color: black;
+  --color: #fff;
+}
+div {
+  display: inline-block;
+  padding: 1rem;
+  background-color: var(--background-color);
+  color: var(--color);
+}

packages/test-data/less/namespacing/namespacing-8.less

@@ -0,0 +1,31 @@
+// see: https://github.com/less/less.js/issues/3368
+@vars: {
+  background-color: black;
+  color: contrast($background-color, #000, #fff);
+}
+
+:root {
+  each(@vars, {
+    --@{key}: @value;
+  });
+}
+
+div {
+  display: inline-block;
+  padding: 1rem;
+  background-color: var(--background-color);
+  color: var(--color);
+}
+
+// see: https://github.com/less/less.js/issues/3339
+// still fails - move to 4.0
+// @components: {
+//   columns: true;
+//   ratios: false;
+// };
+
+// each(@components, {
+//   & when (@value = true) {
+//       @import (optional) "components/@{key}.less";
+//   }
+// });