From e0150b838b371c089e8421d53c19a9e622cf8802 Mon Sep 17 00:00:00 2001
From: NullVoxPopuli <199018+NullVoxPopuli@users.noreply.github.com>
Date: Fri, 20 Feb 2026 11:50:55 -0500
Subject: [PATCH] Extract rule: template-no-block-params-for-html-elements

---
 README.md                                     | 17 ++---
 ...plate-no-block-params-for-html-elements.md | 72 +++++++++++++++++++
 ...plate-no-block-params-for-html-elements.js | 50 +++++++++++++
 ...plate-no-block-params-for-html-elements.js | 54 ++++++++++++++
 4 files changed, 185 insertions(+), 8 deletions(-)
 create mode 100644 docs/rules/template-no-block-params-for-html-elements.md
 create mode 100644 lib/rules/template-no-block-params-for-html-elements.js
 create mode 100644 tests/lib/rules/template-no-block-params-for-html-elements.js

diff --git a/README.md b/README.md
index 5a853147d1..4f98de208e 100644
--- a/README.md
+++ b/README.md
@@ -189,14 +189,15 @@ rules in templates can be disabled with eslint directives with mustache or html
 
 ### Best Practices
 
-| Name                                                                                             | Description                                               | 💼 | 🔧 | 💡 |
-| :----------------------------------------------------------------------------------------------- | :-------------------------------------------------------- | :- | :- | :- |
-| [template-builtin-component-arguments](docs/rules/template-builtin-component-arguments.md)       | disallow setting certain attributes on builtin components |    |    |    |
-| [template-no-action-modifiers](docs/rules/template-no-action-modifiers.md)                       | disallow usage of {{action}} modifiers                    |    |    |    |
-| [template-no-arguments-for-html-elements](docs/rules/template-no-arguments-for-html-elements.md) | disallow @arguments on HTML elements                      |    |    |    |
-| [template-no-array-prototype-extensions](docs/rules/template-no-array-prototype-extensions.md)   | disallow usage of Ember Array prototype extensions        |    |    |    |
-| [template-no-debugger](docs/rules/template-no-debugger.md)                                       | disallow {{debugger}} in templates                        |    |    |    |
-| [template-no-log](docs/rules/template-no-log.md)                                                 | disallow {{log}} in templates                             |    |    |    |
+| Name                                                                                                   | Description                                               | 💼 | 🔧 | 💡 |
+| :----------------------------------------------------------------------------------------------------- | :-------------------------------------------------------- | :- | :- | :- |
+| [template-builtin-component-arguments](docs/rules/template-builtin-component-arguments.md)             | disallow setting certain attributes on builtin components |    |    |    |
+| [template-no-action-modifiers](docs/rules/template-no-action-modifiers.md)                             | disallow usage of {{action}} modifiers                    |    |    |    |
+| [template-no-arguments-for-html-elements](docs/rules/template-no-arguments-for-html-elements.md)       | disallow @arguments on HTML elements                      |    |    |    |
+| [template-no-array-prototype-extensions](docs/rules/template-no-array-prototype-extensions.md)         | disallow usage of Ember Array prototype extensions        |    |    |    |
+| [template-no-block-params-for-html-elements](docs/rules/template-no-block-params-for-html-elements.md) | disallow block params on HTML elements                    |    |    |    |
+| [template-no-debugger](docs/rules/template-no-debugger.md)                                             | disallow {{debugger}} in templates                        |    |    |    |
+| [template-no-log](docs/rules/template-no-log.md)                                                       | disallow {{log}} in templates                             |    |    |    |
 
 ### Components
 
diff --git a/docs/rules/template-no-block-params-for-html-elements.md b/docs/rules/template-no-block-params-for-html-elements.md
new file mode 100644
index 0000000000..9ae6bfb21d
--- /dev/null
+++ b/docs/rules/template-no-block-params-for-html-elements.md
@@ -0,0 +1,72 @@
+# ember/template-no-block-params-for-html-elements
+
+<!-- end auto-generated rule header -->
+
+Disallow block params on HTML elements.
+
+Block params (using the `as |param|` syntax) are a feature specific to Ember components and block helpers. They should not be used on regular HTML elements.
+
+## Rule Details
+
+This rule disallows using block params on HTML elements. Use components if you need to pass block params.
+
+## Examples
+
+### Incorrect ❌
+
+```gjs
+<template>
+  <div as |content|>
+    {{content}}
+  </div>
+</template>
+```
+
+```gjs
+<template>
+  <section as |data|>
+    <p>{{data}}</p>
+  </section>
+</template>
+```
+
+```gjs
+<template>
+  <ul as |items|>
+    <li>{{items}}</li>
+  </ul>
+</template>
+```
+
+### Correct ✅
+
+```gjs
+<template>
+  <div>Content</div>
+</template>
+```
+
+```gjs
+<template>
+  <MyComponent as |item|>
+    {{item.name}}
+  </MyComponent>
+</template>
+```
+
+```gjs
+<template>
+  {{#each this.items as |item|}}
+    <li>{{item}}</li>
+  {{/each}}
+</template>
+```
+
+## Related Rules
+
+- [template-no-arguments-for-html-elements](./template-no-arguments-for-html-elements.md)
+
+## References
+
+- [Ember Guides - Block Content](https://guides.emberjs.com/release/components/block-content/)
+- [eslint-plugin-ember template-no-yield-only](https://github.com/ember-cli/eslint-plugin-ember/blob/master/docs/rules/template-no-yield-only.md)
diff --git a/lib/rules/template-no-block-params-for-html-elements.js b/lib/rules/template-no-block-params-for-html-elements.js
new file mode 100644
index 0000000000..d1f9eb3da6
--- /dev/null
+++ b/lib/rules/template-no-block-params-for-html-elements.js
@@ -0,0 +1,50 @@
+/** @type {import('eslint').Rule.RuleModule} */
+const htmlTags = require('html-tags');
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'disallow block params on HTML elements',
+      category: 'Best Practices',
+      strictGjs: true,
+      strictGts: true,
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-no-block-params-for-html-elements.md',
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      noBlockParamsForHtmlElements:
+        'Block params can only be used with components, not HTML elements.',
+    },
+  },
+
+  create(context) {
+    const sourceCode = context.sourceCode;
+    const HTML_ELEMENTS = new Set(htmlTags);
+
+    return {
+      GlimmerElementNode(node) {
+        // Check if this is an HTML element (lowercase)
+        if (!HTML_ELEMENTS.has(node.tag)) {
+          return;
+        }
+
+        // If the tag name is a variable in scope, it's being used as a component, not an HTML element
+        const scope = sourceCode.getScope(node.parent);
+        const isVariable = scope.references.some((ref) => ref.identifier === node.parts[0]);
+        if (isVariable) {
+          return;
+        }
+
+        // Check for block params
+        if (node.blockParams && node.blockParams.length > 0) {
+          context.report({
+            node,
+            messageId: 'noBlockParamsForHtmlElements',
+          });
+        }
+      },
+    };
+  },
+};
diff --git a/tests/lib/rules/template-no-block-params-for-html-elements.js b/tests/lib/rules/template-no-block-params-for-html-elements.js
new file mode 100644
index 0000000000..c7a50ad9dc
--- /dev/null
+++ b/tests/lib/rules/template-no-block-params-for-html-elements.js
@@ -0,0 +1,54 @@
+const rule = require('../../../lib/rules/template-no-block-params-for-html-elements');
+const RuleTester = require('eslint').RuleTester;
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+ruleTester.run('template-no-block-params-for-html-elements', rule, {
+  valid: [
+    `let div = <template>{{yield "hello"}}</template>;
+    <template>
+      <div as |greeting|>{{greeting}}</div>
+    </template>
+    `,
+    '<template><div>Content</div></template>',
+    '<template><MyComponent as |item|>{{item.name}}</MyComponent></template>',
+    '<template>{{#each this.items as |item|}}<li>{{item}}</li>{{/each}}</template>',
+    '<template><button>Click</button></template>',
+  ],
+
+  invalid: [
+    {
+      code: '<template><div as |content|>{{content}}</div></template>',
+      output: null,
+      errors: [
+        {
+          message: 'Block params can only be used with components, not HTML elements.',
+          type: 'GlimmerElementNode',
+        },
+      ],
+    },
+    {
+      code: '<template><section as |data|><p>{{data}}</p></section></template>',
+      output: null,
+      errors: [
+        {
+          message: 'Block params can only be used with components, not HTML elements.',
+          type: 'GlimmerElementNode',
+        },
+      ],
+    },
+    {
+      code: '<template><ul as |items|><li>{{items}}</li></ul></template>',
+      output: null,
+      errors: [
+        {
+          message: 'Block params can only be used with components, not HTML elements.',
+          type: 'GlimmerElementNode',
+        },
+      ],
+    },
+  ],
+});