fix #1631

plugins/postcss-is-pseudo-class/CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changes to PostCSS Is Pseudo Class
 
+### Unreleased (patch)
+
+- Fix support for more complex selector patterns. `.a > :is(.b > .c)` -> `.a.b > .c`
+
 ### 5.0.2
 
 _June 10, 2025_

plugins/postcss-is-pseudo-class/src/split-selectors/complex/same-preceding-element.ts

@@ -75,6 +75,7 @@ export function samePrecedingElement(selector: parser.Container): boolean {
 	}
 
 	const before = selector.nodes.slice(0, combinatorIndex);
+	const after = selector.nodes.slice(isPseudoIndex + 1);
 
 	selector.each((node) => {
 		node.remove();
@@ -88,5 +89,9 @@ export function samePrecedingElement(selector: parser.Container): boolean {
 		selector.append(node);
 	});
 
+	after.forEach((node) => {
+		selector.append(node);
+	});
+
 	return true;
 }

plugins/postcss-is-pseudo-class/test/complex.css

@@ -324,3 +324,8 @@ console.log(out.join(''));
 .ignore::before + :is(.b + .c) {
 	order: 78;
 }
+
+/* https: //github.com/csstools/postcss-plugins/issues/1631 */
+.c > :is(.a > .b) .d::before {
+	order: 79;
+}

plugins/postcss-is-pseudo-class/test/complex.expect.css

@@ -324,3 +324,8 @@ console.log(out.join(''));
 .ignore::before + :is(.b + .c) {
 	order: 78;
 }
+
+/* https: //github.com/csstools/postcss-plugins/issues/1631 */
+.c.a > .b .d::before {
+	order: 79;
+}