fix(template-require-mandatory-role-attributes): recognize native aria-checked from <input type=checkbox|radio>

The rule required an explicit `aria-checked` on every element with a
role that needs it — even when the host element is a semantic form
control that contributes the state natively.

WAI-ARIA APG documents <input type="checkbox" role="switch"> as an
accessible switch pattern (see https://www.w3.org/WAI/ARIA/apg/patterns/switch/);
the <input>'s native checked state maps to aria-checked.

Fix: when the host is <input type="checkbox"> or <input type="radio">
and the role is one of {checkbox, menuitemcheckbox, menuitemradio,
radio, switch}, treat aria-checked as satisfied.

Matches eslint-plugin-jsx-a11y's role-has-required-aria-props, which
uses axobject-query's isSemanticRoleElement to skip the check for
element+role combinations where the native element already exposes the
required state. Our implementation covers the common cases without
pulling in the axobject-query dependency.

Five new test cases added covering the documented pattern. Rule doc
updated with an explicit example and an APG link.

Author: johanrd

docs/rules/template-require-mandatory-role-attributes.md

@@ -31,9 +31,15 @@ This rule **allows** the following:
   <div role="option" aria-selected="false" />
   <CustomComponent role="checkbox" aria-required="true" aria-checked="false" />
   {{some-component role="heading" aria-level="2"}}
+
+  {{! <input type="checkbox|radio"> supplies aria-checked natively for roles that require it. }}
+  <input type="checkbox" role="switch" />
+  <input type="checkbox" role="menuitemcheckbox" />
+  <input type="radio" role="menuitemradio" />
 </template>
 ```
 
 ## References
 
 - [WAI-ARIA Roles - Accessibility \_ MDN](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Roles)
+- [WAI-ARIA APG — Switch pattern](https://www.w3.org/WAI/ARIA/apg/patterns/switch/) (documents `<input type="checkbox" role="switch">` as an accessible switch)

lib/rules/template-require-mandatory-role-attributes.js

@@ -28,17 +28,54 @@ function getStaticRoleFromMustache(node) {
   return undefined;
 }
 
-function getMissingRequiredAttributes(role, foundAriaAttributes) {
+// Roles whose required `aria-checked` is supplied natively by <input type="checkbox">
+// or <input type="radio">. Per WAI-ARIA APG, semantic form controls contribute
+// implicit state; e.g. <input type="checkbox" role="switch"> is a documented
+// accessible switch pattern where aria-checked mirrors the native checkedness.
+const ROLES_WITH_IMPLICIT_CHECKED_FROM_INPUT = new Set([
+  'checkbox',
+  'menuitemcheckbox',
+  'menuitemradio',
+  'radio',
+  'switch',
+]);
+
+function getInputType(node) {
+  if (node?.tag !== 'input') {
+    return undefined;
+  }
+  const typeAttr = node.attributes?.find((a) => a.name === 'type');
+  if (typeAttr?.value?.type === 'GlimmerTextNode') {
+    return typeAttr.value.chars;
+  }
+  return undefined;
+}
+
+function isNativelyChecked(node, role) {
+  if (!ROLES_WITH_IMPLICIT_CHECKED_FROM_INPUT.has(role)) {
+    return false;
+  }
+  const type = getInputType(node);
+  return type === 'checkbox' || type === 'radio';
+}
+
+function getMissingRequiredAttributes(role, foundAriaAttributes, node) {
   const roleDefinition = roles.get(role);
 
   if (!roleDefinition) {
     return null;
   }
 
   const requiredAttributes = Object.keys(roleDefinition.requiredProps);
-  const missingRequiredAttributes = requiredAttributes.filter(
-    (requiredAttribute) => !foundAriaAttributes.includes(requiredAttribute)
-  );
+  const missingRequiredAttributes = requiredAttributes.filter((requiredAttribute) => {
+    if (foundAriaAttributes.includes(requiredAttribute)) {
+      return false;
+    }
+    if (requiredAttribute === 'aria-checked' && isNativelyChecked(node, role)) {
+      return false;
+    }
+    return true;
+  });
 
   return missingRequiredAttributes.length > 0 ? missingRequiredAttributes : null;
 }
@@ -93,7 +130,11 @@ module.exports = {
           .filter((attribute) => attribute.name?.startsWith('aria-'))
           .map((attribute) => attribute.name);
 
-        const missingRequiredAttributes = getMissingRequiredAttributes(role, foundAriaAttributes);
+        const missingRequiredAttributes = getMissingRequiredAttributes(
+          role,
+          foundAriaAttributes,
+          node
+        );
 
         if (missingRequiredAttributes) {
           reportMissingAttributes(node, role, missingRequiredAttributes);

tests/lib/rules/template-require-mandatory-role-attributes.js

@@ -25,6 +25,15 @@ ruleTester.run('template-require-mandatory-role-attributes', rule, {
     '<template>{{foo-component role="button"}}</template>',
     '<template>{{foo-component role="unknown"}}</template>',
     '<template>{{foo-component role=role}}</template>',
+
+    // Semantic inputs supply aria-checked natively; the role is satisfied
+    // without an explicit aria-checked attribute. Documented accessible
+    // patterns: https://www.w3.org/WAI/ARIA/apg/patterns/switch/#keyboardinteraction
+    '<template><input type="checkbox" role="switch" /></template>',
+    '<template><input type="checkbox" role="menuitemcheckbox" /></template>',
+    '<template><input type="radio" role="menuitemradio" /></template>',
+    '<template><input type="radio" role="radio" /></template>',
+    '<template><input type="checkbox" role="checkbox" /></template>',
   ],
 
   invalid: [
@@ -105,6 +114,13 @@ hbsRuleTester.run('template-require-mandatory-role-attributes', rule, {
     '{{foo-component role="button"}}',
     '{{foo-component role="unknown"}}',
     '{{foo-component role=role}}',
+
+    // Semantic inputs supply aria-checked natively.
+    '<input type="checkbox" role="switch" />',
+    '<input type="checkbox" role="menuitemcheckbox" />',
+    '<input type="radio" role="menuitemradio" />',
+    '<input type="radio" role="radio" />',
+    '<input type="checkbox" role="checkbox" />',
   ],
   invalid: [
     {