diff --git a/src/libexpr/value-to-json.cc b/src/libexpr/value-to-json.cc
index 7c28754f5..1c3849593 100644
--- a/src/libexpr/value-to-json.cc
+++ b/src/libexpr/value-to-json.cc
@@ -65,7 +65,7 @@ void printValueAsJSON(EvalState & state, bool strict,
             auto list(out.list());
             for (unsigned int n = 0; n < v.listSize(); ++n) {
                 auto placeholder(list.placeholder());
-                printValueAsJSON(state, strict, *v.listElems()[n], noPos, placeholder, context);
+                printValueAsJSON(state, strict, *v.listElems()[n], pos, placeholder, context);
             }
             break;
         }