diff --git a/src/expand.cpp b/src/expand.cpp
index 684a1a22a..07b11a9b2 100644
--- a/src/expand.cpp
+++ b/src/expand.cpp
@@ -1002,6 +1002,7 @@ expand_result_t expander_t::stage_cmdsubst(wcstring input, completion_receiver_t
     }
 }
 
+// We pass by value to match other stages. NOLINTNEXTLINE(performance-unnecessary-value-param)
 expand_result_t expander_t::stage_variables(wcstring input, completion_receiver_t *out) {
     // We accept incomplete strings here, since complete uses expand_string to expand incomplete
     // strings from the commandline.