From b04a861ae7af060d9f176b597a4e89eac1012401 Mon Sep 17 00:00:00 2001
From: David Cosgrove <davidacosgroveaz@gmail.com>
Date: Tue, 2 Jun 2026 13:38:14 +0100
Subject: [PATCH] Replace combineMols with RWMol::insertMol. (#9319)

Co-authored-by: David Cosgrove <david@cozchemix.co.uk>
---
 Code/GraphMol/SynthonSpaceSearch/SynthonSet.cpp        |  6 +++---
 .../SynthonSpaceSearch/SynthonSpaceSearch_details.cpp  | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Code/GraphMol/SynthonSpaceSearch/SynthonSet.cpp b/Code/GraphMol/SynthonSpaceSearch/SynthonSet.cpp
index e1133f1a6..c093d9b66 100644
--- a/Code/GraphMol/SynthonSpaceSearch/SynthonSet.cpp
+++ b/Code/GraphMol/SynthonSpaceSearch/SynthonSet.cpp
@@ -228,12 +228,12 @@ std::vector<std::unique_ptr<ROMol>> buildSampleMolecules(
   mzparams.label = MolzipLabel::Isotope;
 
   for (size_t i = 0; i < synthons[longVecNum].size(); ++i) {
-    auto combMol = std::make_unique<ROMol>();
+    auto combMol = std::make_unique<RWMol>();
     for (size_t j = 0; j < synthons.size(); ++j) {
       if (j == longVecNum) {
-        combMol.reset(combineMols(*combMol, *synthons[j][i]));
+        combMol->insertMol(*synthons[j][i]);
       } else {
-        combMol.reset(combineMols(*combMol, *synthons[j].front()));
+        combMol->insertMol(*synthons[j].front());
       }
     }
     try {
diff --git a/Code/GraphMol/SynthonSpaceSearch/SynthonSpaceSearch_details.cpp b/Code/GraphMol/SynthonSpaceSearch/SynthonSpaceSearch_details.cpp
index 1f874327a..2f1e076dc 100644
--- a/Code/GraphMol/SynthonSpaceSearch/SynthonSpaceSearch_details.cpp
+++ b/Code/GraphMol/SynthonSpaceSearch/SynthonSpaceSearch_details.cpp
@@ -841,13 +841,13 @@ std::unique_ptr<ROMol> buildProduct(
     const std::vector<const ROMol *> &synthons) {
   MolzipParams mzparams;
   mzparams.label = MolzipLabel::Isotope;
-  auto prodMol = std::make_unique<ROMol>(*synthons.front());
+  auto prodMol = std::make_unique<RWMol>(*synthons.front());
   for (size_t i = 1; i < synthons.size(); ++i) {
-    prodMol.reset(combineMols(*prodMol, *synthons[i]));
+    prodMol->insertMol(*synthons[i]);
   }
-  prodMol = molzip(*prodMol, mzparams);
-  MolOps::sanitizeMol(*dynamic_cast<RWMol *>(prodMol.get()));
-  return prodMol;
+  auto zipProdMol = molzip(*prodMol, mzparams);
+  MolOps::sanitizeMol(*dynamic_cast<RWMol *>(zipProdMol.get()));
+  return zipProdMol;
 }
 
 std::map<std::string, std::vector<ROMol *>> mapFragsBySmiles(