perfect forwarding to reference

Author: Michal Tichák

Utilities/Mergers/src/MergerAlgorithm.cxx

@@ -18,6 +18,7 @@
 
 #include "Mergers/MergeInterface.h"
 #include "Mergers/ObjectStore.h"
+#include "Framework/Logger.h"
 
 #include <TEfficiency.h>
 #include <TGraph.h>
@@ -52,7 +53,7 @@ size_t estimateTreeSize(TTree* tree)
 // we need to recursively transverse whole TPad structure.
 auto collectUnderlyingObjects(TCanvas* canvas) -> std::vector<TObject*>
 {
-  auto collectFromTPad = [](TPad* pad, std::vector<TObject*>& objects, auto&& collectFromTPad) {
+  auto collectFromTPad = [](TPad* pad, std::vector<TObject*>& objects, const auto& collectFromTPad) {
     if (!pad) {
       return;
     }

Utilities/Mergers/test/test_Algorithm.cxx

@@ -15,8 +15,6 @@
 /// \author Piotr Konopka, piotr.jan.konopka@cern.ch
 
 #include <boost/mpl/pair.hpp>
-#include <boost/test/tools/interface.hpp>
-#include <boost/test/tools/old/interface.hpp>
 #include <gsl/span>
 #include <memory>
 #include <stdexcept>
@@ -323,13 +321,10 @@ TCanvas* createCanvas(std::string name, std::string title, std::vector<std::shar
 
 auto collectUnderlyingObjects(TCanvas* canvas) -> std::vector<TObject*>
 {
-  if (!canvas) {
-    return {};
-  }
-
-  auto collectFromTPad = []<class TPadOrTCanvas>
-    requires std::same_as<TPadOrTCanvas, TPad> || std::same_as<TPadOrTCanvas, TCanvas>
-  (TPadOrTCanvas * pad, std::vector<TObject*> & objects, auto&& collectFromTPad) -> void {
+  auto collectFromTPad = [](TPad* pad, std::vector<TObject*>& objects, const auto& collectFromTPad) {
+    if (!pad) {
+      return;
+    }
     auto* primitives = pad->GetListOfPrimitives();
     for (int i = 0; i < primitives->GetSize(); ++i) {
       auto* primitive = primitives->At(i);