[BUGFIX] Using query params helper outside of link-to

packages/@ember/-internals/glimmer/lib/components/link-to.ts

@@ -3,6 +3,7 @@
 */
 
 import { alias, computed } from '@ember/-internals/metal';
+import { isQueryParams } from '@ember/-internals/routing/lib/system/query_params';
 import { isSimpleClick } from '@ember/-internals/views';
 import { assert, warn } from '@ember/debug';
 import { flaggedInstrument } from '@ember/instrumentation';
@@ -838,13 +839,20 @@ const LinkComponent = EmberComponent.extend({
         )
       );
 
-      if (DEBUG && this.query === UNDEFINED) {
+      if (this.query === UNDEFINED) {
         let { _models: models } = this;
-        let lastModel = models.length > 0 && models[models.length - 1];
+        if (models.length > 0) {
+          let lastModel = models[models.length - 1];
 
+          if (typeof lastModel === 'object' && lastModel !== null && lastModel.isQueryParams) {
+            this.query = lastModel.values;
+            models.pop();
+          }
+        }
+      } else {
         assert(
-          'The `(query-params)` helper can only be used when invoking the `{{link-to}}` component.',
-          !(lastModel && lastModel.isQueryParams)
+          'Cannot pass a QueryParams object in @models and @query at the same time',
+          !(this.models.length === 0 || isQueryParams(this.models[this.models.length - 1]))
         );
       }
 

packages/@ember/-internals/glimmer/tests/integration/components/link-to/query-params-curly-test.js

@@ -76,13 +76,16 @@ moduleFor(
 
       this.addTemplate(
         'index',
-        `{{#let (query-params foo='456' bar='NAW') as |qp|}}{{link-to 'Index' 'index' qp}}{{/let}}`
+        `{{#let (query-params foo='456' alon='BUKAI') as |qp|}}{{link-to 'Index' 'index' qp}}{{/let}}`
       );
 
-      return assert.rejectsAssertion(
-        this.visit('/'),
-        /The `\(query-params\)` helper can only be used when invoking the `{{link-to}}` component\./
-      );
+      return this.visit('/').then(() => {
+        this.assertComponentElement(this.firstChild, {
+          tagName: 'a',
+          attrs: { href: '/?alon=BUKAI&foo=456', class: classMatcher('ember-view') },
+          content: 'Index',
+        });
+      });
     }
   }
 );

packages/@ember/-internals/routing/lib/system/query_params.ts

@@ -1,7 +1,13 @@
+import { Option } from '@glimmer/interfaces';
+
 export default class QueryParams {
   values: null | object;
   isQueryParams = true;
-  constructor(values = null) {
+  constructor(values: Option<object> = null) {
     this.values = values;
   }
 }
+
+export function isQueryParams(obj: unknown): obj is QueryParams {
+  return typeof obj === 'object' && obj !== null && obj['isQueryParams'] === true;
+}