Replace ranges::views::partial_sum with transform on clang to avoid a crash

Phys/DecayTreeTupleTracking/src/TupleToolTrackKink.cpp

@@ -141,17 +141,34 @@ StatusCode TupleToolTrackKink::kinkChi2( const LHCb::Track& track, double& chi2k
 
   int N = measnodes.size();
   // Get chi2 in the forward direction up to each node
+#ifdef __clang__
+  double partial = 0.0;
+#endif
   auto chi2forward = measnodes | ranges::views::transform( []( const LHCb::FitNode* node ) {
                        return node ? node->deltaChi2Forward().chi2() : 0;
                      } ) |
-                     ranges::views::partial_sum | ranges::to<std::vector<double>>();
+#ifdef __clang__
+                     ranges::views::transform( [&partial]( double elem ) { return ( partial += elem ); } ) |
+#else
+                     // this  causes a crash in clang
+                     ranges::views::partial_sum |
+#endif
+                     ranges::to<std::vector<double>>();
 
   // Get chi2 in the backward direction up to each node
+#ifdef __clang__
+  partial = 0.0;
+#endif
   auto deltaChi2backward = measnodes | ranges::views::reverse |
                            ranges::views::transform( []( const LHCb::FitNode* node ) {
                              return node ? node->deltaChi2Backward().chi2() : 0;
                            } ) |
+#ifdef __clang__
+                           ranges::views::transform( [&partial]( double elem ) { return ( partial += elem ); } );
+#else
+                           // this  causes a crash in clang
                            ranges::views::partial_sum;
+#endif
   std::vector<double> chi2backward( N, 0 );
   ranges::copy( deltaChi2backward, chi2backward.rbegin() );