diff --git a/phpstan.neon b/phpstan.neon
index b19da80279e..2872d2d05ab 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -319,6 +319,7 @@ parameters:
             identifier: symplify.forbiddenFuncCall
             paths:
                 - src/functions/node_helper.php
+                - src/functions/rule_class_aliases.php
                 - src/Util/Reflection/PrivatesAccessor.php
 
         # it may return array<Node|null> in case of empty array( , , ), very rare and would nullify all other types
diff --git a/src/functions/rule_class_aliases.php b/src/functions/rule_class_aliases.php
index 9e5338a8f0d..9545970c31f 100644
--- a/src/functions/rule_class_aliases.php
+++ b/src/functions/rule_class_aliases.php
@@ -9,13 +9,16 @@
 
 // backward-compatibility aliases for rules retargeted to Class_/ClassLike nodes and moved out of the ClassMethod namespace,
 // so configs and 3rd party sets referencing the former namespace keep working
-$ruleClassAliases = [
-    ChangeMethodVisibilityRector::class => 'Rector\Visibility\Rector\ClassMethod\ChangeMethodVisibilityRector',
-    RemoveParentDelegatingClassMethodRector::class => 'Rector\DeadCode\Rector\ClassMethod\RemoveParentDelegatingClassMethodRector',
-    ReturnTypeFromMockObjectRector::class => 'Rector\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromMockObjectRector',
-    AddVoidReturnTypeWhereNoReturnRector::class => 'Rector\TypeDeclaration\Rector\ClassMethod\AddVoidReturnTypeWhereNoReturnRector',
+$legacyToCurrentRuleClasses = [
+    'Rector\Visibility\Rector\ClassMethod\ChangeMethodVisibilityRector' => ChangeMethodVisibilityRector::class,
+    'Rector\DeadCode\Rector\ClassMethod\RemoveParentDelegatingClassMethodRector' => RemoveParentDelegatingClassMethodRector::class,
+    'Rector\TypeDeclaration\Rector\ClassMethod\ReturnTypeFromMockObjectRector' => ReturnTypeFromMockObjectRector::class,
+    'Rector\TypeDeclaration\Rector\ClassMethod\AddVoidReturnTypeWhereNoReturnRector' => AddVoidReturnTypeWhereNoReturnRector::class,
 ];
 
-foreach ($ruleClassAliases as $currentClass => $legacyClass) {
-    class_alias($currentClass, $legacyClass);
-}
+// register lazily, so the current rule classes are only loaded when the legacy name is actually requested
+spl_autoload_register(static function (string $class) use ($legacyToCurrentRuleClasses): void {
+    if (isset($legacyToCurrentRuleClasses[$class])) {
+        class_alias($legacyToCurrentRuleClasses[$class], $class);
+    }
+});