Fix null ref

src/Psalm/Internal/Analyzer/CommentAnalyzer.php

@@ -577,9 +577,9 @@ class CommentAnalyzer
             || isset($comments['specials']['extends'])
         ) {
             $all_inheritance = array_merge(
-                $comments['specials']['template-extends'] ?: [],
+                $comments['specials']['template-extends'] ?? [],
-                $comments['specials']['inherits'] ?: [],
+                $comments['specials']['inherits'] ?? [],
-                $comments['specials']['extends'] ?: []
+                $comments['specials']['extends'] ?? []
             );
 
             foreach ($all_inheritance as $template_line) {

tests/TemplateTest.php

@@ -1627,6 +1627,56 @@ class TemplateTest extends TestCase
                     '$f2' => 'Foo',
                 ]
             ],
+            'supportBareExtends' => [
+                '<?php
+                    /**
+                     * @template T
+                     */
+                    abstract class Container
+                    {
+                        /**
+                         * @return T
+                         */
+                        public abstract function getItem();
+                    }
+
+                    class Foo
+                    {
+                    }
+
+                    /**
+                     * @extends Container<Foo>
+                     */
+                    class FooContainer extends Container
+                    {
+                        /**
+                         * @return Foo
+                         */
+                        public function getItem()
+                        {
+                            return new Foo();
+                        }
+                    }
+
+                    /**
+                     * @template TItem
+                     * @param Container<TItem> $c
+                     * @return TItem
+                     */
+                    function getItemFromContainer(Container $c) {
+                        return $c->getItem();
+                    }
+
+                    $fc = new FooContainer();
+
+                    $f1 = $fc->getItem();
+                    $f2 = getItemFromContainer($fc);',
+                [
+                    '$fc' => 'FooContainer',
+                    '$f1' => 'Foo',
+                    '$f2' => 'Foo',
+                ]
+            ],
             'allowExtendingParameterisedTypeParam' => [
                 '<?php
                     /**