diff --git a/dumux/common/splinecommon_.hh b/dumux/common/splinecommon_.hh
index e38a5859ad42ab6cc7d5836dfe7056bd1c33551b..872672fc2592686a6c3a7da387d3eaa3652d4bcc 100644
--- a/dumux/common/splinecommon_.hh
+++ b/dumux/common/splinecommon_.hh
@@ -85,7 +85,6 @@ public:
         const int n = numSamples_() - 1;
         for (int i = 0; i <= k; ++i) {
             double x = i*(x1 - x0)/k + x0;
-            double x_p1 = x + (x1 - x0)/k;
             double y;
             double dy_dx;
             double mono = 1;
@@ -108,6 +107,7 @@ public:
             else {
                 y = eval(x);
                 dy_dx = evalDerivative(x);
+                double x_p1 = x + (x1 - x0)/k;
                 mono = monotonic(max<Scalar>(x_(0), x), min<Scalar>(x_(n), x_p1));
             }
 
diff --git a/dumux/geometry/makegeometry.hh b/dumux/geometry/makegeometry.hh
index a52258df1e6601f307e9c17d9186f1ec8cd81601..18e205c8f0797ed2ccb395e3bde6f3951cffdf7b 100644
--- a/dumux/geometry/makegeometry.hh
+++ b/dumux/geometry/makegeometry.hh
@@ -119,9 +119,9 @@ std::vector<Dune::FieldVector<CoordScalar, 3>> getReorderedPoints(const std::vec
 
         // the points do not conform with the dune ordering, re-order
         using GlobalPosition = Dune::FieldVector<CoordScalar, 3>;
-        if(!diagonalsIntersect && orientations[0] == 1)
+        if(orientations[0] == 1)
             return std::vector<GlobalPosition>{p1, p0, p2, p3};
-        else if(!diagonalsIntersect && orientations[0] == -1)
+        else if(orientations[0] == -1)
             return std::vector<GlobalPosition>{p3, p1, p0, p2};
         else
             DUNE_THROW(Dune::InvalidStateException, "Could not reorder points");
diff --git a/dumux/material/fluidsystems/h2oairxylene.hh b/dumux/material/fluidsystems/h2oairxylene.hh
index 810d3601f425d58502921dc771b94faeb293b72f..e7fc270537b2fb39f6b9be38fb8569afa27e2062 100644
--- a/dumux/material/fluidsystems/h2oairxylene.hh
+++ b/dumux/material/fluidsystems/h2oairxylene.hh
@@ -372,8 +372,6 @@ public:
                                        int phaseIdx,
                                        int compIdx)
     {
-        Scalar diffCont;
-
         Scalar temperature = fluidState.temperature(phaseIdx);
         Scalar pressure = fluidState.pressure(phaseIdx);
         if (phaseIdx==gPhaseIdx) {
@@ -402,6 +400,8 @@ public:
             Scalar xww = fluidState.moleFraction(wPhaseIdx, H2OIdx);
             Scalar xwc = fluidState.moleFraction(wPhaseIdx, NAPLIdx);
 
+            Scalar diffCont;
+
             switch (compIdx) {
             case NAPLIdx:
                 diffCont = (1.- xww)/(xwa/diffAWl + xwc/diffWCl);
diff --git a/test/common/functionfromstringexpression/test_functionfromstringexpression.cc b/test/common/functionfromstringexpression/test_functionfromstringexpression.cc
index e97865af37d9f3942047517ade83793e3067ad39..9c75c93add0249dd84421f838f28415019355520 100644
--- a/test/common/functionfromstringexpression/test_functionfromstringexpression.cc
+++ b/test/common/functionfromstringexpression/test_functionfromstringexpression.cc
@@ -70,7 +70,7 @@ int main(int argc, char* argv[])
         const std::string funcStr = "foo*sin(bar)*bla";
         bool error = false;
         try { FunctionFromStringExpression<2> func(funcStr, std::array<std::string, 2>{{"foo" "bar"}}); }
-        catch (Dune::IOError& e) { error = true; }
+        catch (const Dune::IOError& e) { error = true; }
         if (!error)
             DUNE_THROW(Dune::Exception, "Faulty expression did not throw: " << funcStr);
     }
diff --git a/test/common/spline/test_spline.cc b/test/common/spline/test_spline.cc
index 30249beeb237ed030bfe2dca1aea8c79bebe46b4..10f8a086f19d0fd23d2348a497c359fe8e299a1a 100644
--- a/test/common/spline/test_spline.cc
+++ b/test/common/spline/test_spline.cc
@@ -240,8 +240,8 @@ void plot()
     double y_[] = { 10, 0, 10, 0, 10 };
     double m1 = 10;
     double m2 = -10;
-    FV &xs = *reinterpret_cast<FV*>(x_);
-    FV &ys = *reinterpret_cast<FV*>(y_);
+    const FV &xs = *reinterpret_cast<FV*>(x_);
+    const FV &ys = *reinterpret_cast<FV*>(y_);
 
     Dumux::Spline<double, numSamples> spFull(xs, ys, m1, m2);
     Dumux::Spline<double, numSamples> spNatural(xs, ys);
diff --git a/test/geometry/test_1d2d_intersection.cc b/test/geometry/test_1d2d_intersection.cc
index d4cf483f194350337b9e38d21f4453f9b9709500..0deac74958710f914ddb1faf1f73def390d956c9 100644
--- a/test/geometry/test_1d2d_intersection.cc
+++ b/test/geometry/test_1d2d_intersection.cc
@@ -26,7 +26,7 @@ Dune::MultiLinearGeometry<double, 1, 3>
 makeLine(std::initializer_list<Dune::FieldVector<double, 2>>&& c, std::integral_constant<int, 3>)
 {
     std::vector<Dune::FieldVector<double, 3>> corners;
-    for (auto& corner : c)
+    for (const auto& corner : c)
     {
         Dune::FieldVector<double, 3> coord;
         coord[0] = corner[0];