diff --git a/src/one-body-sample.cc b/src/one-body-sample.cc
index e76d5db45fc76896a7505148bbb6b8dcef2386c2..9058bf1eba7de51dbf0f6b6bc02762701dd58b52 100644
--- a/src/one-body-sample.cc
+++ b/src/one-body-sample.cc
@@ -334,8 +334,7 @@ int main(int argc, char *argv[]) {
 
     auto const timesteps = parset.get<size_t>("timeSteps");
     auto const tau = parset.get<double>("endOfTime") / timesteps;
-
-    auto createRHS = [&](double _time, VectorType &_ell) {
+    auto const createRHS = [&](double _time, VectorType &_ell) {
       assemble_neumann<GridType, GridView, SmallVector, P1Basis>(
           leafView, p1Basis, neumannNodes, _ell, neumannFunction, _time);
       _ell += gravityFunctional;