Fix collectChildNodes to include parts during node traversal

Author: tcjr

lib/rules/template-no-unused-block-params.js

@@ -24,6 +24,11 @@ function collectChildNodes(n) {
   if (n.children) {
     children.push(...n.children);
   }
+  // GlimmerPathExpression also has 'parts', so make sure we're not treating
+  // concat'd path string parts as AST nodes.
+  if (n.type === 'GlimmerConcatStatement' && n.parts) {
+    children.push(...n.parts);
+  }
   return children;
 }
 

tests/lib/rules/template-no-unused-block-params.js

@@ -118,6 +118,11 @@ const invalidHbs = [
     output: null,
     errors: [{ messageId: 'unusedBlockParam', data: { param: 'cat' } }],
   },
+  {
+    code: `{{#each cats as |cat|}}{{a.different.cat}}{{/each}}`,
+    output: null,
+    errors: [{ messageId: 'unusedBlockParam', data: { param: 'cat' } }],
+  },
 ];
 
 function wrapTemplate(entry) {