diff --git a/src/Psalm/Internal/Codebase/ClassLikes.php b/src/Psalm/Internal/Codebase/ClassLikes.php
index faae088d7..bfdcc9934 100644
--- a/src/Psalm/Internal/Codebase/ClassLikes.php
+++ b/src/Psalm/Internal/Codebase/ClassLikes.php
@@ -716,7 +716,8 @@ class ClassLikes
     public function getUnAliasedName(string $alias_name)
     {
         $alias_name_lc = strtolower($alias_name);
-        if (isset($this->existing_classlikes_lc[$alias_name_lc])) {
+
+        if ($this->existing_classlikes_lc[$alias_name_lc] ?? false) {
             return $alias_name;
         }
 
diff --git a/tests/ClassTest.php b/tests/ClassTest.php
index f7f4be909..ec57d7956 100644
--- a/tests/ClassTest.php
+++ b/tests/ClassTest.php
@@ -429,6 +429,20 @@ class ClassTest extends TestCase
                 [],
                 ['PropertyNotSetInConstructor'],
             ],
+            'classAliasNoException' => [
+                '<?php
+                    class_alias("Bar\F1", "Bar\F2");
+
+                    namespace Bar {
+                        class F1 {
+                            public static function baz() : void {}
+                        }
+                    }
+
+                    namespace {
+                        Bar\F2::baz();
+                    }',
+            ],
         ];
     }