Add -Wnull-dereference warning and fix issues

cmake/traccc-compiler-options-cpp.cmake

@@ -23,6 +23,8 @@ if( ( "${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU" ) OR
    traccc_add_flag( CMAKE_CXX_FLAGS "-Wshadow" )
    traccc_add_flag( CMAKE_CXX_FLAGS "-Wunused-local-typedefs" )
    traccc_add_flag( CMAKE_CXX_FLAGS "-pedantic" )
+   traccc_add_flag( CMAKE_CXX_FLAGS "-Wold-style-cast" )
+   traccc_add_flag( CMAKE_CXX_FLAGS "-Wnull-dereference" )
    if(PROJECT_IS_TOP_LEVEL)
      traccc_add_flag( CMAKE_CXX_FLAGS "-Wfloat-conversion" )
    endif()

core/include/traccc/seeding/spacepoint_binning_helper.hpp

@@ -99,7 +99,8 @@ inline std::pair<detray::axis2::circular<>, detray::axis2::regular<>> get_axes(
 
     scalar zBinSize = grid_config.cotThetaMax * grid_config.deltaRMax;
     detray::dindex zBins = std::max(
-        1, (int)std::floor((grid_config.zMax - grid_config.zMin) / zBinSize));
+        1, static_cast<int>(
+               std::floor((grid_config.zMax - grid_config.zMin) / zBinSize)));
 
     detray::axis2::regular m_z_axis{zBins, grid_config.zMin, grid_config.zMax,
                                     mr};

extern/tbb/CMakeLists.txt

@@ -29,3 +29,10 @@ set( TBB_STRICT FALSE CACHE BOOL "Do not throw errors on compiler warnings" )
 
 # Get it into the current directory.
 FetchContent_MakeAvailable( TBB )
+
+# Treat the TBB headers as "system headers", to avoid getting warnings from
+# them.
+get_target_property( _incDirs tbb INTERFACE_INCLUDE_DIRECTORIES )
+target_include_directories( tbb
+   SYSTEM INTERFACE ${_incDirs} )
+unset( _incDirs )

io/src/csv/read_cells.cpp

@@ -58,7 +58,7 @@ traccc::cell_module get_module(const std::uint64_t geometry_id,
         }
 
         // Set the value on the module description.
-        result.placement = (*geom)[result.surface_link.value()];
+        result.placement = geom->at(result.surface_link.value());
     }
 
     // Find/set the digitization configuration of the detector module.

io/src/csv/read_spacepoints.cpp

@@ -59,7 +59,7 @@ void read_spacepoints(spacepoint_reader_output& out, std::string_view filename,
             m[iohit.geometry_id] = link;
             cell_module mod;
             mod.surface_link = detray::geometry::barcode{iohit.geometry_id};
-            mod.placement = geom[iohit.geometry_id];
+            mod.placement = geom.at(iohit.geometry_id);
             result_modules.push_back(mod);
         }