diff --git a/dune/solvers/iterationsteps/blockgssteps.hh b/dune/solvers/iterationsteps/blockgssteps.hh
index cc51211477e523342f164e252314ce5316b37be0..c5b3b02e7135923ed0d996bbc14450ee14217b0a 100644
--- a/dune/solvers/iterationsteps/blockgssteps.hh
+++ b/dune/solvers/iterationsteps/blockgssteps.hh
@@ -164,7 +164,8 @@ auto truncate(LinearSolver&& linearSolver) {
 
     auto mTruncated = m;
     auto bTruncated = b;
-    assert(b.size() == m.N() && m.N() == m.M());
+    assert(b.size() == m.N());
+    assert(m.N() == m.M());
     size_t blockSize = b.size();
     for (size_t j = 0; j < blockSize; ++j) {
       if (not ignore[j])
@@ -260,8 +261,7 @@ auto cg(size_t maxIter = LinearSolvers::defaultCgMaxIter,
 
 /**
  * \brief A Gauss--Seidel-type linear iteration step.
- * \param localSolver The solver how to solve the linear block correction
- * problems.
+ * \param localSolver The solver for the linear block correction problems.
  */
 template <class Matrix, class Vector, class BitVector, class LocalSolver>
 struct BlockGSStep : public LinearIterationStep<Matrix, Vector, BitVector> {