fix: no-duplicate-selectors false positives for SCSS/Less nested interpolations (#6118)

Author: JounQin

lib/rules/no-duplicate-selectors/__tests__/index.js

@@ -358,6 +358,14 @@ testRule({
 			code: 'a { background: { color: red } }',
 			description: 'Non standard SCSS nested property',
 		},
+		{
+			code: '.#{foo} { &:last-child { &, & > .#{foo}-bar {} } }',
+			description: 'Non standard SCSS nested interpolation',
+		},
+		{
+			code: 'a { b, .#{var} {} b {} }',
+			description: 'Non standard SCSS nested interpolation (2',
+		},
 	],
 });
 
@@ -371,5 +379,13 @@ testRule({
 			code: '.@{foo} { .@{foo}-bar {} }',
 			description: 'Non standard Less nested interpolation',
 		},
+		{
+			code: '.@{foo} { &:last-child { &, & > .@{foo}-bar {} } }',
+			description: 'Non standard Less nested interpolation (2',
+		},
+		{
+			code: 'a { b, .@{var} {} b {} }',
+			description: 'Non standard Less nested interpolation (3',
+		},
 	],
 });

lib/rules/no-duplicate-selectors/index.js

@@ -63,18 +63,10 @@ const rule = (primary, secondaryOptions) => {
 			);
 			const resolvedSelectorList = [
 				...new Set(
-					ruleNode.selectors.flatMap((selector) => {
-						return isStandardSyntaxSelector(selector)
-							? resolvedNestedSelector(selector, ruleNode)
-							: [];
-					}),
+					ruleNode.selectors.flatMap((selector) => resolvedNestedSelector(selector, ruleNode)),
 				),
 			];
 
-			if (resolvedSelectorList.length === 0) {
-				return;
-			}
-
 			const normalizedSelectorList = resolvedSelectorList.map(normalize);
 
 			// Sort the selectors list so that the order of the constituents
@@ -133,10 +125,6 @@ const rule = (primary, secondaryOptions) => {
 
 			// Or complain if one selector list contains the same selector more than once
 			for (const selector of ruleNode.selectors) {
-				if (!isStandardSyntaxSelector(selector)) {
-					continue;
-				}
-
 				const normalized = normalize(selector);
 
 				if (presentedSelectors.has(normalized)) {
@@ -175,6 +163,10 @@ const rule = (primary, secondaryOptions) => {
  * @returns {string}
  */
 function normalize(selector) {
+	if (!isStandardSyntaxSelector(selector)) {
+		return selector;
+	}
+
 	return selectorParser().processSync(selector, { lossless: false });
 }