diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 84c28abe1a5..7d703ffe062 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -74,6 +74,7 @@ namespace ts {
     /**
      * Creates a deep, memberwise clone of a node with no source map location.
      */
+    /* @internal */
     export function getSynthesizedDeepClone<T extends Node>(node: T | undefined): T | undefined {
         return node
             ? getSynthesizedClone(visitEachChild(node, child => getSynthesizedDeepClone(child), nullTransformationContext))