Merge branch 'issue/wrong-warning-diagonalmatrix-assigner' into 'master'

Improve the error message in the DenseMatrixAssigner for DiagonalMatrix

See merge request !1480

dune/common/diagonalmatrix.hh

@@ -1106,8 +1106,11 @@ namespace Dune {
   struct DenseMatrixAssigner<DenseMatrix, DiagonalMatrix<field, N>> {
     static void apply(DenseMatrix& denseMatrix,
                       DiagonalMatrix<field, N> const& rhs) {
-      DUNE_ASSERT_BOUNDS(denseMatrix.M() == N);
-      DUNE_ASSERT_BOUNDS(denseMatrix.N() == N);
+#ifdef DUNE_CHECK_BOUNDS
+      if (denseMatrix.M() != N || denseMatrix.N() != N)
+        DUNE_THROW(Dune::RangeError, "Incompatible matrix dimensions in assignment.");
+#endif // DUNE_CHECK_BOUNDS
+
       denseMatrix = field(0);
       for (int i = 0; i < N; ++i)
         denseMatrix[i][i] = rhs.diagonal()[i];