diff --git a/bin/improve_class_alias.php b/bin/improve_class_alias.php
index f6f051048..6b6f34ff2 100644
--- a/bin/improve_class_alias.php
+++ b/bin/improve_class_alias.php
@@ -13,22 +13,24 @@ $search = '/* @var FullyQualified $originalName */
 $replace = '/* @var FullyQualified $originalName */
         $aliasStmt = $this->createAliasStmt($originalName, $stmt);
 
-        $stmts[] = new If_(
-            new FuncCall(
-                new FullyQualified(\'class_exists\'),
-                [
-                    new Node\Arg(
-                        new Node\Expr\ClassConstFetch(
-                            $originalName,
-                            \'class\'
+        $stmts[] = new Node\Stmt\If_(
+            new Node\Expr\BooleanNot(
+                new Node\Expr\FuncCall(
+                    new FullyQualified(\'class_exists\'),
+                    [
+                        new Node\Arg(
+                            new Node\Expr\ClassConstFetch(
+                                $originalName,
+                                \'class\'
+                            )
+                        ),
+                        new Node\Arg(
+                            new Node\Expr\ConstFetch(
+                                new Node\Name(\'false\')
+                            )
                         )
-                    ),
-                    new Node\Arg(
-                        new Node\Expr\ConstFetch(
-                            new Node\Name(\'false\')
-                        )
-                    )
-                ]
+                    ]
+                )
             ),
             [\'stmts\' => [$aliasStmt]]
         );';