Fix template-no-block-params-for-html-elements: align HTML-element detection with upstream

Replace static htmlTags package check with inverse-of-component-detection
(reject tags with : / . / uppercase / @ / -). Custom elements like
<my-element as |x|> are no longer false-flagged.

Author: johanrd

lib/rules/template-no-block-params-for-html-elements.js

@@ -1,5 +1,34 @@
 /** @type {import('eslint').Rule.RuleModule} */
-const htmlTags = require('html-tags');
+
+// Mirror upstream ember-template-lint's inverse-of-isAngleBracketComponent logic.
+// A tag is treated as an HTML element only when it:
+//   - does NOT contain ':' (named blocks like <:slot>)
+//   - does NOT contain '.' (path/namespaced invocations like <foo.bar>)
+//   - does NOT start with '@' (argument invocations like <@foo>)
+//   - has NO uppercase letters (component invocations like <MyThing>)
+//   - does NOT contain '-' (HTML custom elements like <my-element>)
+// Everything else is a component / custom-element / slot — not a plain HTML element.
+function isHtmlElement(tagName) {
+  if (!tagName) {
+    return false;
+  }
+  if (tagName.startsWith('@')) {
+    return false;
+  }
+  if (tagName.includes(':')) {
+    return false;
+  }
+  if (tagName.includes('.')) {
+    return false;
+  }
+  if (tagName.includes('-')) {
+    return false;
+  }
+  if (tagName !== tagName.toLowerCase()) {
+    return false;
+  }
+  return true;
+}
 
 module.exports = {
   meta: {
@@ -20,12 +49,11 @@ module.exports = {
 
   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)) {
+        // Check if this is an HTML element (not a component / custom element / slot)
+        if (!isHtmlElement(node.tag)) {
           return;
         }
 

tests/lib/rules/template-no-block-params-for-html-elements.js

@@ -17,6 +17,11 @@ ruleTester.run('template-no-block-params-for-html-elements', rule, {
     '<template><MyComponent as |item|>{{item.name}}</MyComponent></template>',
     '<template>{{#each this.items as |item|}}<li>{{item}}</li>{{/each}}</template>',
     '<template><button>Click</button></template>',
+    // Custom elements (with a dash) are not HTML elements per upstream's
+    // isAngleBracketComponent inverse; they should not be flagged.
+    '<template><my-element as |x|>{{x}}</my-element></template>',
+    // Namespaced/path component invocations should not be treated as HTML elements.
+    '<template><NS.Foo as |x|>{{x}}</NS.Foo></template>',
   ],
 
   invalid: [