diff --git a/cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll b/cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll
index 929a91ccf09..deac133016f 100644
--- a/cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll
+++ b/cpp/ql/lib/semmle/code/cpp/dataflow/ExternalFlow.qll
@@ -362,7 +362,7 @@ module CsvValidation {
       output.matches("ReturnValue%") and
       result =
         "Constructor model for " + namespace + "." + type +
-          " should use `Argument[-1]` in the output, not `ReturnValue`."
+          " should use `Argument[this]` in the output, not `ReturnValue`."
     )
   }