diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll
index f90910b319e..024e9cf119d 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/ExternalFlow.qll
@@ -239,7 +239,7 @@ module ModelValidation {
     )
   }
 
-  string getIncorrectConstructorSummaryOutput() {
+  private string getIncorrectConstructorSummaryOutput() {
     exists(string namespace, string type, string name, string output |
       type = name or
       type = name + "<" + any(string s)