Fix Wshadow warnings

(cherry picked from commit 889dd5bd)
Signed-off-by: Steffen Müthing <muething@dune-project.org>

dune/geometry/genericgeometry/matrixhelper.hh

@@ -260,11 +260,11 @@ namespace Dune
         {
           FieldType &rii = ret[ i ][ i ];
 
-          FieldType x = A[ i ][ i ];
+          FieldType xDiag = A[ i ][ i ];
           for( int j = 0; j < i; ++j )
-            x -= ret[ i ][ j ] * ret[ i ][ j ];
-          assert( x > FieldType( 0 ) );
-          rii = sqrt( x );
+            xDiag -= ret[ i ][ j ] * ret[ i ][ j ];
+          assert( xDiag > FieldType( 0 ) );
+          rii = sqrt( xDiag );
 
           FieldType invrii = FieldType( 1 ) / rii;
           for( int k = i+1; k < n; ++k )

dune/geometry/test/checkgeometry.hh

@@ -93,9 +93,9 @@ namespace Dune
     // Use a quadrature rule as a set of test points and loop over them
     ///////////////////////////////////////////////////////////////////////////////
     const Dune::QuadratureRule<ctype, mydim> & quadrature = Dune::QuadratureRules<ctype, mydim>::rule(geometry.type(), 2);
-    for( size_t i = 0; i < quadrature.size(); ++i )
+    for (const auto& ip : quadrature)
     {
-      const typename TestGeometry::LocalCoordinate &x = quadrature[ i ].position();
+      const typename TestGeometry::LocalCoordinate &x = ip.position();
 
       // Test whether the methods 'local' and 'global' are inverse to each other
       if ( (x - geometry.local( geometry.global( x ) )).two_norm() > 1e-8 ) {

dune/geometry/test/test-multilineargeometry.cc

@@ -121,21 +121,21 @@ static bool testMultiLinearGeometry ( const Dune::ReferenceElement< ctype, mydim
   }
 
   for (int c = 0; c < numCorners; ++c) {
-    const Dune::FieldMatrix< ctype, mydim, cdim > JT = geometry.jacobianTransposed(refElement.position(c, mydim));
+    const Dune::FieldMatrix< ctype, mydim, cdim > cornerJT = geometry.jacobianTransposed(refElement.position(c, mydim));
     for( int i = 0; i < mydim; ++i ) {
       Dune::FieldVector< ctype, mydim > e( ctype( 0 ) );
       e[ i ] = ctype( 1 );
       const Dune::FieldVector< ctype, cdim > t = map( A, B, e );
-      if (JT[i] != JT[i])
+      if (cornerJT[i] != cornerJT[i])
       {
         std::cerr << "Error: at corner " << c << ": jacobianTransposed["
-                  << i << "] (" << JT[i] << ") has NaN entry." << std::endl;
+                  << i << "] (" << cornerJT[i] << ") has NaN entry." << std::endl;
         pass = false;
       }
-      if( (t - JT[ i ]).two_norm() > epsilon )
+      if( (t - cornerJT[ i ]).two_norm() > epsilon )
       {
         std::cerr << "Error: at corner " << c << ": wrong jacobianTransposed[ "
-                  << i << " ] (" << JT[ i ] << ", should be " << t << ")."
+                  << i << " ] (" << cornerJT[ i ] << ", should be " << t << ")."
                   << std::endl;
         pass = false;
       }