From 6b5bc49b75a541c037684a61f69455aad146371c Mon Sep 17 00:00:00 2001
From: Bart Veneman <bartveneman@gmail.com>
Date: Thu, 15 Oct 2026 13:59:06 +0200
Subject: [PATCH] fix: make sure to check for case sensitivity in more places

---
 src/defined-used.test.ts   | 12 ++++++++++++
 src/index.ts               | 21 ++++++++++-----------
 src/string-utils.ts        |  2 --
 src/values/browserhacks.ts |  6 +++---
 4 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/defined-used.test.ts b/src/defined-used.test.ts
index 51fa88d9..a53cc927 100644
--- a/src/defined-used.test.ts
+++ b/src/defined-used.test.ts
@@ -91,6 +91,12 @@ describe('Custom properties', () => {
 		expect(result.used).toEqual(['--color'])
 	})
 
+	test('tracks VAR() references as used regardless of case', () => {
+		let css = `.foo { color: VAR(--color); }`
+		let result = analyze(css).properties.custom
+		expect(result.used).toEqual(['--color'])
+	})
+
 	test('identifies unused custom properties', () => {
 		let css = `:root { --color: red; --size: 16px; } .foo { color: var(--color); }`
 		let result = analyze(css).properties.custom
@@ -384,6 +390,12 @@ describe('Anchor names', () => {
 		expect(result.used).toContain('--my-anchor')
 	})
 
+	test('tracks ANCHOR() and ANCHOR-SIZE() functions as used regardless of case', () => {
+		let css = `.positioned { position: absolute; top: ANCHOR(--my-anchor bottom); width: ANCHOR-SIZE(--my-anchor width); }`
+		let result = analyze(css).properties.anchorNames
+		expect(result.used).toContain('--my-anchor')
+	})
+
 	test('identifies unused anchor names', () => {
 		let css = `
 			.anchor { anchor-name: --tooltip; }
diff --git a/src/index.ts b/src/index.ts
index 800c5e9c..aea77b03 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,6 +3,7 @@ import {
 	type CSSNode,
 	is_custom,
 	SKIP,
+	str_equals,
 	str_starts_with,
 	walk,
 	parse,
@@ -730,7 +731,7 @@ function analyzeInternal<T extends boolean>(css: string, options: Options, useLo
 					}
 				} else if (normalizedProperty === 'anchor-name') {
 					for (let child of value.children) {
-						if (is_identifier(child) && str_starts_with(child.text, '--')) {
+						if (is_identifier(child) && is_custom(child.text)) {
 							anchorNamesTracking.define(child.text)
 						}
 					}
@@ -738,7 +739,7 @@ function analyzeInternal<T extends boolean>(css: string, options: Options, useLo
 					if (
 						value.first_child &&
 						is_identifier(value.first_child) &&
-						str_starts_with(value.first_child.text, '--')
+						is_custom(value.first_child.text)
 					) {
 						anchorNamesTracking.use(value.first_child.text)
 					}
@@ -832,21 +833,19 @@ function analyzeInternal<T extends boolean>(css: string, options: Options, useLo
 						let firstFuncChild = valueNode.first_child
 
 						// Track var(--custom-property) usage
-						if (
-							funcName === 'var' &&
-							firstFuncChild &&
-							is_identifier(firstFuncChild) &&
-							str_starts_with(firstFuncChild.text, '--')
-						) {
-							customPropsTracking.use(firstFuncChild.text)
+						if (str_equals('var', funcName) && firstFuncChild && is_identifier(firstFuncChild)) {
+							let name = firstFuncChild.text
+							if (is_custom(name)) {
+								customPropsTracking.use(name)
+							}
 						}
 
 						// Track anchor(--name) and anchor-size(--name) usage
 						if (
-							(funcName === 'anchor' || funcName === 'anchor-size') &&
+							(str_equals('anchor', funcName) || str_equals('anchor-size', funcName)) &&
 							firstFuncChild &&
 							is_identifier(firstFuncChild) &&
-							str_starts_with(firstFuncChild.text, '--')
+							is_custom(firstFuncChild.text)
 						) {
 							anchorNamesTracking.use(firstFuncChild.text)
 						}
diff --git a/src/string-utils.ts b/src/string-utils.ts
index ff94399a..a0e77360 100644
--- a/src/string-utils.ts
+++ b/src/string-utils.ts
@@ -1,5 +1,3 @@
-import { str_equals, str_starts_with } from '@projectwallace/css-parser'
-
 export function unquote(str: string): string {
 	return str.replaceAll(/(?:^['"])|(?:['"]$)/g, '')
 }
diff --git a/src/values/browserhacks.ts b/src/values/browserhacks.ts
index 56a4063b..1ce1c691 100644
--- a/src/values/browserhacks.ts
+++ b/src/values/browserhacks.ts
@@ -4,6 +4,7 @@ import {
 	is_identifier,
 	is_function,
 	is_url,
+	str_equals,
 	walk,
 } from '@projectwallace/css-parser'
 import { endsWith, unquote } from '../string-utils.js'
@@ -48,10 +49,9 @@ export function isValueBrowserhack(node: Value, on_hack: (hack: string) => void)
 	// alpha(), expression(), and behavior .htc hacks
 	walk(node, function (child) {
 		if (is_function(child)) {
-			const name = child.name.toLowerCase()
-			if (name === 'alpha') {
+			if (str_equals('alpha', child.name)) {
 				on_hack('alpha()')
-			} else if (name === 'expression') {
+			} else if (str_equals('expression', child.name)) {
 				on_hack('expression()')
 			}
 		}