diff --git a/lib/reference/properties.cjs b/lib/reference/properties.cjs
index ba102496c2..0299d9e3d4 100644
--- a/lib/reference/properties.cjs
+++ b/lib/reference/properties.cjs
@@ -15,7 +15,6 @@ const acceptCustomIdentsProperties = new Set([
 	'list-style-type',
 ]);
 
-/** @type {import('stylelint').ShorthandToResetToInitialProperty} */
 const shorthandToResetToInitialProperty = new Map([
 	[
 		'border',
@@ -29,6 +28,7 @@ const shorthandToResetToInitialProperty = new Map([
 		]),
 	],
 	[
+		/** @see https://www.w3.org/TR/css-fonts-4/#font-prop */
 		'font',
 		new Set([
 			// prettier-ignore
diff --git a/lib/reference/properties.mjs b/lib/reference/properties.mjs
index bf9eee7ed7..c1547e3e8e 100644
--- a/lib/reference/properties.mjs
+++ b/lib/reference/properties.mjs
@@ -11,7 +11,6 @@ export const acceptCustomIdentsProperties = new Set([
 	'list-style-type',
 ]);
 
-/** @type {import('stylelint').ShorthandToResetToInitialProperty} */
 export const shorthandToResetToInitialProperty = new Map([
 	[
 		'border',
@@ -25,6 +24,7 @@ export const shorthandToResetToInitialProperty = new Map([
 		]),
 	],
 	[
+		/** @see https://www.w3.org/TR/css-fonts-4/#font-prop */
 		'font',
 		new Set([
 			// prettier-ignore
diff --git a/lib/rules/declaration-block-no-shorthand-property-overrides/index.cjs b/lib/rules/declaration-block-no-shorthand-property-overrides/index.cjs
index 6b54258591..ec62ccdade 100644
--- a/lib/rules/declaration-block-no-shorthand-property-overrides/index.cjs
+++ b/lib/rules/declaration-block-no-shorthand-property-overrides/index.cjs
@@ -5,6 +5,7 @@
 const eachDeclarationBlock = require('../../utils/eachDeclarationBlock.cjs');
 const report = require('../../utils/report.cjs');
 const ruleMessages = require('../../utils/ruleMessages.cjs');
+const uniteSets = require('../../utils/uniteSets.cjs');
 const validateOptions = require('../../utils/validateOptions.cjs');
 const vendor = require('../../utils/vendor.cjs');
 const properties = require('../../reference/properties.cjs');
@@ -43,7 +44,7 @@ const rule = (primary) => {
 					properties.shorthandToResetToInitialProperty
 				).get(unprefixedProp);
 				// see microsoft/TypeScript#57228
-				const union = new Set([...(subProperties ?? []), ...(resettables ?? [])]);
+				const union = uniteSets(subProperties ?? [], resettables ?? []);
 
 				declarations.set(prop.toLowerCase(), prop);
 
diff --git a/lib/rules/declaration-block-no-shorthand-property-overrides/index.mjs b/lib/rules/declaration-block-no-shorthand-property-overrides/index.mjs
index 805be88f17..eb3b8ef83e 100644
--- a/lib/rules/declaration-block-no-shorthand-property-overrides/index.mjs
+++ b/lib/rules/declaration-block-no-shorthand-property-overrides/index.mjs
@@ -1,6 +1,7 @@
 import eachDeclarationBlock from '../../utils/eachDeclarationBlock.mjs';
 import report from '../../utils/report.mjs';
 import ruleMessages from '../../utils/ruleMessages.mjs';
+import uniteSets from '../../utils/uniteSets.mjs';
 import validateOptions from '../../utils/validateOptions.mjs';
 import vendor from '../../utils/vendor.mjs';
 
@@ -43,7 +44,7 @@ const rule = (primary) => {
 					shorthandToResetToInitialProperty
 				).get(unprefixedProp);
 				// see microsoft/TypeScript#57228
-				const union = new Set([...(subProperties ?? []), ...(resettables ?? [])]);
+				const union = uniteSets(subProperties ?? [], resettables ?? []);
 
 				declarations.set(prop.toLowerCase(), prop);
 
diff --git a/types/stylelint/index.d.mts b/types/stylelint/index.d.mts
index e41a98829f..61d0c025ca 100644
--- a/types/stylelint/index.d.mts
+++ b/types/stylelint/index.d.mts
@@ -40,7 +40,6 @@ export {
 	RuleSeverity,
 	Severity,
 	ShorthandProperties,
-	ShorthandToResetToInitialProperty,
 	StylelintPostcssResult,
 	Utils,
 	Warning,
diff --git a/types/stylelint/index.d.ts b/types/stylelint/index.d.ts
index 7b6c5c2d5c..11fccc4c68 100644
--- a/types/stylelint/index.d.ts
+++ b/types/stylelint/index.d.ts
@@ -681,10 +681,6 @@ declare namespace stylelint {
 		| 'text-emphasis'
 		| 'transition';
 
-	type ImplicitResetters = Extract<ShorthandProperties, 'border' | 'flex' | 'font'>;
-	/** @internal */
-	export type ShorthandToResetToInitialProperty = ReadonlyMap<ImplicitResetters, Set<string>>;
-
 	/** @internal */
 	export type LonghandSubPropertiesOfShorthandProperties = ReadonlyMap<
 		ShorthandProperties,