diff --git a/src/OpenFOAM/meshes/polyMesh/syncTools/dummyTransform.H b/src/OpenFOAM/meshes/polyMesh/syncTools/dummyTransform.H
index 3f803d7847..355c5f9e9c 100644
--- a/src/OpenFOAM/meshes/polyMesh/syncTools/dummyTransform.H
+++ b/src/OpenFOAM/meshes/polyMesh/syncTools/dummyTransform.H
@@ -32,8 +32,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef dummyTransform_H
-#define dummyTransform_H
+#ifndef Foam_dummyTransform_H
+#define Foam_dummyTransform_H
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
diff --git a/src/OpenFOAM/meshes/polyMesh/syncTools/syncTools.H b/src/OpenFOAM/meshes/polyMesh/syncTools/syncTools.H
index be8f76ef98..43b5fb8af4 100644
--- a/src/OpenFOAM/meshes/polyMesh/syncTools/syncTools.H
+++ b/src/OpenFOAM/meshes/polyMesh/syncTools/syncTools.H
@@ -42,8 +42,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef syncTools_H
-#define syncTools_H
+#ifndef Foam_syncTools_H
+#define Foam_syncTools_H
 
 #include "Pstream.H"
 #include "edgeHashes.H"
@@ -170,7 +170,7 @@ public:
                 UList<T>& faceValues,
                 const CombineOp& cop,
                 const TransformOp& top,
-                const bool parRun = Pstream::parRun()
+                const bool parRun = UPstream::parRun()
             );
 
 
@@ -609,7 +609,7 @@ public:
                 const bool isBoundaryOnly,
                 PackedList<Width>& faceValues,
                 const CombineOp& cop,
-                const bool parRun = Pstream::parRun()
+                const bool parRun = UPstream::parRun()
             );
 
             //- Synchronize mesh face values from PackedList/bitSet
@@ -619,7 +619,7 @@ public:
                 const polyMesh& mesh,
                 PackedList<Width>& faceValues,
                 const CombineOp& cop,
-                const bool parRun = Pstream::parRun()
+                const bool parRun = UPstream::parRun()
             );
 
             //- Synchronize boundary face values from PackedList/bitSet
@@ -629,7 +629,7 @@ public:
                 const polyMesh& mesh,
                 PackedList<Width>& faceValues,
                 const CombineOp& cop,
-                const bool parRun = Pstream::parRun()
+                const bool parRun = UPstream::parRun()
             );
 
             //- Swap coupled face values. Uses eqOp
diff --git a/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C b/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
index ac4015a8ec..f24116864f 100644
--- a/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
+++ b/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -48,7 +48,7 @@ void Foam::syncTools::combine
 
     if (iter.good())
     {
-        cop(*iter, val);
+        cop(iter.val(), val);
     }
     else
     {
@@ -70,7 +70,7 @@ void Foam::syncTools::combine
 
     if (iter.good())
     {
-        cop(*iter, val);
+        cop(iter.val(), val);
     }
     else
     {
@@ -118,17 +118,17 @@ void Foam::syncTools::syncPointMap
                     sharedPointValues,
                     cop,
                     sharedPtAddr[i],    // index
-                    *fnd                // value
+                    fnd.val()           // value
                 );
             }
         }
     }
 
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         DynamicList<label> neighbProcs;
-        PstreamBuffers pBufs(Pstream::commsTypes::nonBlocking);
+        PstreamBuffers pBufs(UPstream::commsTypes::nonBlocking);
 
         // Send
         for (const polyPatch& pp : patches)
@@ -140,7 +140,7 @@ void Foam::syncTools::syncPointMap
                 const auto& procPatch = *ppp;
                 const label nbrProci = procPatch.neighbProcNo();
 
-                neighbProcs.append(nbrProci);
+                neighbProcs.push_back(nbrProci);
 
                 // Get data per patchPoint in neighbouring point numbers.
 
@@ -157,7 +157,7 @@ void Foam::syncTools::syncPointMap
 
                     if (iter.good())
                     {
-                        patchInfo.insert(nbrPts[i], *iter);
+                        patchInfo.insert(nbrPts[i], iter.val());
                     }
                 }
 
@@ -300,14 +300,14 @@ void Foam::syncTools::syncPointMap
 
         // Reduce on master.
 
-        if (Pstream::parRun())
+        if (UPstream::parRun())
         {
-            if (Pstream::master())
+            if (UPstream::master())
             {
                 // Receive the edges using shared points from other procs
-                for (const int proci : Pstream::subProcs())
+                for (const int proci : UPstream::subProcs())
                 {
-                    IPstream fromProc(Pstream::commsTypes::scheduled, proci);
+                    IPstream fromProc(UPstream::commsTypes::scheduled, proci);
                     Map<T> nbrValues(fromProc);
 
                     // Merge neighbouring values with my values
@@ -328,8 +328,8 @@ void Foam::syncTools::syncPointMap
                 // Send to master
                 OPstream toMaster
                 (
-                    Pstream::commsTypes::scheduled,
-                    Pstream::masterNo()
+                    UPstream::commsTypes::scheduled,
+                    UPstream::masterNo()
                 );
                 toMaster << sharedPointValues;
             }
@@ -355,7 +355,7 @@ void Foam::syncTools::syncPointMap
 
             if (sharedFnd.good())
             {
-                pointValues.set(*iter, *sharedFnd);
+                pointValues.set(iter.val(), sharedFnd.val());
             }
         }
     }
@@ -381,10 +381,10 @@ void Foam::syncTools::syncEdgeMap
     // Swap proc patch info
     // ~~~~~~~~~~~~~~~~~~~~
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         DynamicList<label> neighbProcs;
-        PstreamBuffers pBufs(Pstream::commsTypes::nonBlocking);
+        PstreamBuffers pBufs(UPstream::commsTypes::nonBlocking);
 
         // Send
         for (const polyPatch& pp : patches)
@@ -396,7 +396,7 @@ void Foam::syncTools::syncEdgeMap
                 const auto& procPatch = *ppp;
                 const label nbrProci = procPatch.neighbProcNo();
 
-                neighbProcs.append(nbrProci);
+                neighbProcs.push_back(nbrProci);
 
                 // Get data per patch edge in neighbouring edge.
 
@@ -408,14 +408,14 @@ void Foam::syncTools::syncEdgeMap
 
                 for (const edge& e : edges)
                 {
-                    const edge meshEdge(meshPts[e[0]], meshPts[e[1]]);
+                    const edge meshEdge(meshPts, e);
 
                     const auto iter = edgeValues.cfind(meshEdge);
 
                     if (iter.good())
                     {
-                        const edge nbrEdge(nbrPts[e[0]], nbrPts[e[1]]);
-                        patchInfo.insert(nbrEdge, *iter);
+                        const edge nbrEdge(nbrPts, e);
+                        patchInfo.insert(nbrEdge, iter.val());
                     }
                 }
 
@@ -515,7 +515,7 @@ void Foam::syncTools::syncEdgeMap
 
                     if (iter.good())
                     {
-                        half0Values.insert(edgei, *iter);
+                        half0Values.insert(edgei, iter.val());
                     }
                 }
                 {
@@ -526,7 +526,7 @@ void Foam::syncTools::syncEdgeMap
 
                     if (iter.good())
                     {
-                        half1Values.insert(edgei, *iter);
+                        half1Values.insert(edgei, iter.val());
                     }
                 }
             }
@@ -653,14 +653,14 @@ void Foam::syncTools::syncEdgeMap
     //  shared edge).
     // Reduce this on the master.
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
-        if (Pstream::master())
+        if (UPstream::master())
         {
             // Receive the edges using shared points from other procs
-            for (const int proci : Pstream::subProcs())
+            for (const int proci : UPstream::subProcs())
             {
-                IPstream fromProc(Pstream::commsTypes::scheduled, proci);
+                IPstream fromProc(UPstream::commsTypes::scheduled, proci);
                 EdgeMap<T> nbrValues(fromProc);
 
                 // Merge neighbouring values with my values
@@ -682,8 +682,8 @@ void Foam::syncTools::syncEdgeMap
             {
                 OPstream toMaster
                 (
-                    Pstream::commsTypes::scheduled,
-                    Pstream::masterNo()
+                    UPstream::commsTypes::scheduled,
+                    UPstream::masterNo()
                 );
                 toMaster << sharedEdgeValues;
             }
@@ -772,7 +772,7 @@ void Foam::syncTools::syncPointList
 
         if (iter.good())
         {
-            cppFld[*iter] = pointValues[i];
+            cppFld[iter.val()] = pointValues[i];
         }
     }
 
@@ -793,7 +793,7 @@ void Foam::syncTools::syncPointList
 
         if (iter.good())
         {
-            pointValues[i] = cppFld[*iter];
+            pointValues[i] = cppFld[iter.val()];
         }
     }
 }
@@ -1028,7 +1028,7 @@ void Foam::syncTools::syncBoundaryFaceList
         if
         (
             is_contiguous<T>::value
-         && Pstream::defaultCommsType == Pstream::commsTypes::nonBlocking
+         && UPstream::defaultCommsType == UPstream::commsTypes::nonBlocking
         )
         {
             const label startRequest = UPstream::nRequests();
@@ -1054,7 +1054,7 @@ void Foam::syncTools::syncBoundaryFaceList
 
                     UIPstream::read
                     (
-                        Pstream::commsTypes::nonBlocking,
+                        UPstream::commsTypes::nonBlocking,
                         procPatch.neighbProcNo(),
                         fld.data_bytes(),
                         fld.size_bytes()
@@ -1080,7 +1080,7 @@ void Foam::syncTools::syncBoundaryFaceList
 
                     UOPstream::write
                     (
-                        Pstream::commsTypes::nonBlocking,
+                        UPstream::commsTypes::nonBlocking,
                         procPatch.neighbProcNo(),
                         fld.cdata_bytes(),
                         fld.size_bytes()
@@ -1126,7 +1126,7 @@ void Foam::syncTools::syncBoundaryFaceList
         else
         {
             DynamicList<label> neighbProcs;
-            PstreamBuffers pBufs(Pstream::commsTypes::nonBlocking);
+            PstreamBuffers pBufs(UPstream::commsTypes::nonBlocking);
 
             // Send
             for (const polyPatch& pp : patches)
@@ -1138,7 +1138,7 @@ void Foam::syncTools::syncBoundaryFaceList
                     const auto& procPatch = *ppp;
                     const label nbrProci = procPatch.neighbProcNo();
 
-                    neighbProcs.append(nbrProci);
+                    neighbProcs.push_back(nbrProci);
 
                     const SubList<T> fld
                     (
@@ -1289,7 +1289,7 @@ void Foam::syncTools::syncFaceList
 
                 UIPstream::read
                 (
-                    Pstream::commsTypes::nonBlocking,
+                    UPstream::commsTypes::nonBlocking,
                     procPatch.neighbProcNo(),
                     recvInfo.data_bytes(),
                     recvInfo.size_bytes()
@@ -1324,7 +1324,7 @@ void Foam::syncTools::syncFaceList
 
                 UOPstream::write
                 (
-                    Pstream::commsTypes::nonBlocking,
+                    UPstream::commsTypes::nonBlocking,
                     procPatch.neighbProcNo(),
                     sendInfo.cdata_bytes(),
                     sendInfo.size_bytes()
@@ -1333,7 +1333,7 @@ void Foam::syncTools::syncFaceList
         }
 
         // Wait for all comms to finish
-        Pstream::waitRequests(startRequest);
+        UPstream::waitRequests(startRequest);
 
         // Combine with existing data
         for (const polyPatch& pp : patches)
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PatchTools/PatchToolsGatherAndMerge.C b/src/OpenFOAM/meshes/primitiveMesh/PatchTools/PatchToolsGatherAndMerge.C
index d4dff1f351..750d148387 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PatchTools/PatchToolsGatherAndMerge.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PatchTools/PatchToolsGatherAndMerge.C
@@ -92,7 +92,7 @@ void Foam::PatchTools::gatherAndMerge
 
     labelList boundaryPoints;
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         const globalIndex localPointAddr
         (
@@ -117,7 +117,7 @@ void Foam::PatchTools::gatherAndMerge
     }
 
 
-    if (Pstream::parRun() && Pstream::master())
+    if (UPstream::parRun() && UPstream::master())
     {
         labelList pointToUnique;
 
@@ -206,7 +206,7 @@ void Foam::PatchTools::gatherAndMerge
 {
     typedef typename FaceList::value_type FaceType;
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         // Renumber the points/faces into unique points
         globalPointsPtr = mesh.globalData().mergePoints
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatch.H b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatch.H
index 0c83b4c273..95046da8f4 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatch.H
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatch.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2022 OpenCFD Ltd.
+    Copyright (C) 2016-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -111,6 +111,7 @@ public:
     // Public Data Types
 
         //- Enumeration defining the surface type. Used in check routines.
+        //  Ordered from 'good' to 'bad'
         enum surfaceTopo
         {
             MANIFOLD,
@@ -242,10 +243,10 @@ private:
         void visitPointRegion
         (
             const label pointi,
-            const labelList& pFaces,
+            const labelUList& pFaces,
             const label startFacei,
-            const label startEdgeI,
-            boolList& pFacesHad
+            const label startEdgei,
+            UList<bool>& pFacesVisited
         ) const;
 
 
@@ -525,12 +526,14 @@ public:
 
     // Check
 
-        //- Calculate surface type formed by patch.
-        //  Types:
+        //- Calculate surface type formed by patch,
+        //- optionally recording the indices of illegal edges.
+        //
+        //  Return types:
         //  - all edges have two neighbours (manifold)
         //  - some edges have more than two neighbours (illegal)
         //  - other (open)
-        surfaceTopo surfaceType() const;
+        surfaceTopo surfaceType(labelHashSet* badEdgesPtr = nullptr) const;
 
         //- Check surface formed by patch for manifoldness (see above).
         //  Return true if any incorrect edges are found.
@@ -538,7 +541,7 @@ public:
         bool checkTopology
         (
             const bool report = false,
-            labelHashSet* setPtr = nullptr
+            labelHashSet* pointSetPtr = nullptr
         ) const;
 
         //- Checks primitivePatch for faces sharing point but not edge.
@@ -550,7 +553,7 @@ public:
         bool checkPointManifold
         (
             const bool report = false,
-            labelHashSet* setPtr = nullptr
+            labelHashSet* pointSetPtr = nullptr
         ) const;
 
 
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchCheck.C b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchCheck.C
index ff1fef3f3c..d8c7454e50 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchCheck.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchCheck.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -31,7 +31,7 @@ Description
 
 #include "PrimitivePatch.H"
 #include "Map.H"
-#include "ListOps.H"
+#include "DynamicList.H"
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
@@ -40,60 +40,54 @@ void
 Foam::PrimitivePatch<FaceList, PointField>::visitPointRegion
 (
     const label pointi,
-    const labelList& pFaces,
+    const labelUList& pFaces,
     const label startFacei,
-    const label startEdgeI,
-    boolList& pFacesHad
+    const label startEdgei,
+    UList<bool>& pFacesVisited
 ) const
 {
-    label index = pFaces.find(startFacei);
+    const label index = pFaces.find(startFacei);
 
-    if (!pFacesHad[index])
+    if (index >= 0 && !pFacesVisited[index])
     {
-        // Mark face as been visited.
-        pFacesHad[index] = true;
+        // Mark face as visited
+        pFacesVisited[index] = true;
 
         // Step to next edge on face which is still using pointi
-        const labelList& fEdges = faceEdges()[startFacei];
+        label nextEdgei = -1;
 
-        label nextEdgeI = -1;
-
-        forAll(fEdges, i)
+        for (const label faceEdgei : faceEdges()[startFacei])
         {
-            label edgeI = fEdges[i];
+            const edge& e = edges()[faceEdgei];
 
-            const edge& e = edges()[edgeI];
-
-            if (edgeI != startEdgeI && (e[0] == pointi || e[1] == pointi))
+            if (faceEdgei != startEdgei && e.contains(pointi))
             {
-                nextEdgeI = edgeI;
-
+                nextEdgei = faceEdgei;
                 break;
             }
         }
 
-        if (nextEdgeI == -1)
+        if (nextEdgei == -1)
         {
             FatalErrorInFunction
-                << "Problem: cannot find edge out of " << fEdges
+                << "Problem: cannot find edge out of "
+                << faceEdges()[startFacei]
                 << "on face " << startFacei << " that uses point " << pointi
-                << " and is not edge " << startEdgeI << abort(FatalError);
+                << " and is not edge " << startEdgei << abort(FatalError);
         }
 
         // Walk to next face(s) across edge.
-        const labelList& eFaces = edgeFaces()[nextEdgeI];
-
-        forAll(eFaces, i)
+        for (const label edgeFacei : edgeFaces()[nextEdgei])
         {
-            if (eFaces[i] != startFacei)
+            if (edgeFacei != startFacei)
             {
                 visitPointRegion
                 (
                     pointi,
                     pFaces,
-                    eFaces[i],
-                    nextEdgeI,
-                    pFacesHad
+                    edgeFacei,
+                    nextEdgei,
+                    pFacesVisited
                 );
             }
         }
@@ -105,33 +99,56 @@ Foam::PrimitivePatch<FaceList, PointField>::visitPointRegion
 
 template<class FaceList, class PointField>
 typename Foam::PrimitivePatch<FaceList, PointField>::surfaceTopo
-Foam::PrimitivePatch<FaceList, PointField>::surfaceType() const
+Foam::PrimitivePatch<FaceList, PointField>::surfaceType
+(
+    labelHashSet* badEdgesPtr
+) const
 {
-    DebugInFunction << "Calculating patch topology" << nl;
+    if (badEdgesPtr)
+    {
+        badEdgesPtr->clear();
+    }
+
+    bool foundError = false;
+
+    surfaceTopo pType = surfaceTopo::MANIFOLD;
 
     const labelListList& edgeFcs = edgeFaces();
 
-    surfaceTopo pType = MANIFOLD;
-
-    forAll(edgeFcs, edgeI)
+    forAll(edgeFcs, edgei)
     {
-        label nNbrs = edgeFcs[edgeI].size();
+        const label nNbrs = edgeFcs[edgei].size();
 
         if (nNbrs < 1 || nNbrs > 2)
         {
-            pType = ILLEGAL;
+            // Surface is illegal
+            foundError = true;
 
-            // Can exit now. Surface is illegal.
-            return pType;
+            if (badEdgesPtr)
+            {
+                // Record and continue
+                if (nNbrs > 2)
+                {
+                    badEdgesPtr->insert(edgei);
+                }
+            }
+            else
+            {
+                // Early exit when not recording bad edges
+                break;
+            }
         }
         else if (nNbrs == 1)
         {
             // Surface might be open or illegal so keep looping.
-            pType = OPEN;
+            pType = surfaceTopo::OPEN;
         }
     }
 
-    DebugInFunction << "Calculated patch topology" << nl;
+    if (foundError)
+    {
+        return surfaceTopo::ILLEGAL;
+    }
 
     return pType;
 }
@@ -142,45 +159,40 @@ bool
 Foam::PrimitivePatch<FaceList, PointField>::checkTopology
 (
     const bool report,
-    labelHashSet* setPtr
+    labelHashSet* pointSetPtr
 ) const
 {
-    DebugInFunction << "Checking patch topology" << nl;
-
     // Check edgeFaces
 
+    bool foundError = false;
+
     const labelListList& edgeFcs = edgeFaces();
 
-    bool illegalTopo = false;
-
-    forAll(edgeFcs, edgeI)
+    forAll(edgeFcs, edgei)
     {
-        label nNbrs = edgeFcs[edgeI].size();
+        const label nNbrs = edgeFcs[edgei].size();
 
         if (nNbrs < 1 || nNbrs > 2)
         {
-            illegalTopo = true;
+            foundError = true;
 
             if (report)
             {
-                Info<< "Edge " << edgeI << " with vertices:" << edges()[edgeI]
-                    << " has " << nNbrs << " face neighbours"
-                    << endl;
+                Info<< "Edge " << edgei << " with vertices:" << edges()[edgei]
+                    << " has " << nNbrs << " face neighbours" << endl;
             }
 
-            if (setPtr)
+            if (pointSetPtr)
             {
-                const edge& e = edges()[edgeI];
+                const edge& e = edges()[edgei];
 
-                setPtr->insert(meshPoints()[e.start()]);
-                setPtr->insert(meshPoints()[e.end()]);
+                pointSetPtr->insert(meshPoints()[e.first()]);
+                pointSetPtr->insert(meshPoints()[e.second()]);
             }
         }
     }
 
-    DebugInFunction << "Checked patch topology" << nl;
-
-    return illegalTopo;
+    return foundError;
 }
 
 
@@ -189,7 +201,7 @@ bool
 Foam::PrimitivePatch<FaceList, PointField>::checkPointManifold
 (
     const bool report,
-    labelHashSet* setPtr
+    labelHashSet* pointSetPtr
 ) const
 {
     const labelListList& pf = pointFaces();
@@ -199,47 +211,48 @@ Foam::PrimitivePatch<FaceList, PointField>::checkPointManifold
 
     bool foundError = false;
 
+    // Visited faces (as indices into pFaces)
+    DynamicList<bool> pFacesVisited;
+
     forAll(pf, pointi)
     {
         const labelList& pFaces = pf[pointi];
 
-        // Visited faces (as indices into pFaces)
-        boolList pFacesHad(pFaces.size(), false);
+        pFacesVisited.resize_nocopy(pFaces.size());
+        pFacesVisited = false;
 
         // Starting edge
         const labelList& pEdges = pe[pointi];
-        label startEdgeI = pEdges[0];
+        const label startEdgei = pEdges[0];
 
-        const labelList& eFaces = ef[startEdgeI];
+        const labelList& eFaces = ef[startEdgei];
 
-        forAll(eFaces, i)
+        for (const label edgeFacei : eFaces)
         {
             // Visit all faces using pointi, starting from eFaces[i] and
-            // startEdgeI. Mark off all faces visited in pFacesHad.
+            // startEdgei. Mark off all faces visited in pFacesVisited.
             this->visitPointRegion
             (
                 pointi,
                 pFaces,
-                eFaces[i],  // starting face for walk
-                startEdgeI, // starting edge for walk
-                pFacesHad
+                edgeFacei,  // starting face for walk
+                startEdgei, // starting edge for walk
+                pFacesVisited
             );
         }
 
         // After this all faces using pointi should have been visited and
-        // marked off in pFacesHad.
+        // marked off in pFacesVisited.
 
-        label unset = pFacesHad.find(false);
-
-        if (unset != -1)
+        if (pFacesVisited.contains(false))
         {
             foundError = true;
 
-            label meshPointi = mp[pointi];
+            const label meshPointi = mp[pointi];
 
-            if (setPtr)
+            if (pointSetPtr)
             {
-                setPtr->insert(meshPointi);
+                pointSetPtr->insert(meshPointi);
             }
 
             if (report)
@@ -251,18 +264,18 @@ Foam::PrimitivePatch<FaceList, PointField>::checkPointManifold
                     << " is multiply connected at this point" << nl
                     << "Connected (patch) faces:" << nl;
 
-                forAll(pFacesHad, i)
+                forAll(pFacesVisited, i)
                 {
-                    if (pFacesHad[i])
+                    if (pFacesVisited[i])
                     {
                         Info<< "    " << pFaces[i] << endl;
                     }
                 }
 
                 Info<< nl << "Unconnected (patch) faces:" << nl;
-                forAll(pFacesHad, i)
+                forAll(pFacesVisited, i)
                 {
-                    if (!pFacesHad[i])
+                    if (!pFacesVisited[i])
                     {
                         Info<< "    " << pFaces[i] << endl;
                     }
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchEdgeLoops.C b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchEdgeLoops.C
index 8b19fb5320..6d15926d6f 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchEdgeLoops.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchEdgeLoops.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020-2021 OpenCFD Ltd.
+    Copyright (C) 2020-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -50,7 +50,7 @@ Foam::PrimitivePatch<FaceList, PointField>::calcEdgeLoops() const
 
     const edgeList& patchEdges = edges();
     const label nIntEdges = nInternalEdges();
-    const label nBdryEdges = patchEdges.size() - nIntEdges;
+    const label nBdryEdges = (patchEdges.size() - nIntEdges);
 
     // Size return list plenty big
     edgeLoopsPtr_.reset(new labelListList(nBdryEdges));
@@ -68,74 +68,61 @@ Foam::PrimitivePatch<FaceList, PointField>::calcEdgeLoops() const
     // Walk point-edge-point and assign loop number
     //
 
-    // Loop per (boundary) edge.
-    labelList loopNumber(nBdryEdges, -1);
+    // Temporary storage for vertices of current loop
+    DynamicList<label> loop(nBdryEdges);
 
-    // Current loop number.
-    label loopI = 0;
+    // In a loop? - per boundary edge
+    boolList unvisited(nBdryEdges, true);
 
-    while (true)
+    // Current loop number
+    label numLoops = 0;
+
+    // Walk all boundary edges not yet in a loop
+    for
+    (
+        label bndEdgei = -1;
+        (bndEdgei = unvisited.find(true)) >= 0;
+        /*nil*/
+    )
     {
-        // Find edge not yet given a loop number.
-        label currentEdgeI = -1;
-
-        for (label edgeI = nIntEdges; edgeI < patchEdges.size(); edgeI++)
-        {
-            if (loopNumber[edgeI-nIntEdges] == -1)
-            {
-                currentEdgeI = edgeI;
-                break;
-            }
-        }
-
-        if (currentEdgeI == -1)
-        {
-            // Did not find edge not yet assigned a loop number so done all.
-            break;
-        }
-
-        // Temporary storage for vertices of current loop
-        DynamicList<label> loop(nBdryEdges);
+        label currentEdgei = (bndEdgei + nIntEdges);
 
         // Walk from first all the way round, assigning loops
-        label currentVertI = patchEdges[currentEdgeI].start();
+        label currentVerti = patchEdges[currentEdgei].first();
+
+        loop.clear();
 
         do
         {
-            loop.append(currentVertI);
+            loop.push_back(currentVerti);
 
-            loopNumber[currentEdgeI - nIntEdges] = loopI;
+            unvisited[currentEdgei - nIntEdges] = false;
 
             // Step to next vertex
-            currentVertI = patchEdges[currentEdgeI].otherVertex(currentVertI);
+            currentVerti = patchEdges[currentEdgei].otherVertex(currentVerti);
 
             // Step to next (unmarked, boundary) edge.
-            const labelList& curEdges = patchPointEdges[currentVertI];
+            currentEdgei = -1;
 
-            currentEdgeI = -1;
-
-            forAll(curEdges, pI)
+            for (const label edgei : patchPointEdges[currentVerti])
             {
-                label edgeI = curEdges[pI];
-
-                if (edgeI >= nIntEdges && (loopNumber[edgeI - nIntEdges] == -1))
+                if (edgei >= nIntEdges && unvisited[edgei - nIntEdges])
                 {
-                    // Unassigned boundary edge.
-                    currentEdgeI = edgeI;
-
+                    // Unvisited boundary edge
+                    currentEdgei = edgei;
                     break;
                 }
             }
         }
-        while (currentEdgeI != -1);
+        while (currentEdgei != -1);
 
-        // Done all for current loop. Transfer to edgeLoops.
-        edgeLoops[loopI].transfer(loop);
+        // Done all for current loop - copy to edgeLoops
+        edgeLoops[numLoops] = loop;
 
-        loopI++;
+        ++numLoops;
     }
 
-    edgeLoops.setSize(loopI);
+    edgeLoops.resize(numLoops);
 
     DebugInFunction << "Calculated boundary edge loops" << nl;
 }
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
index a58efd3385..c75900e850 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
@@ -90,7 +90,7 @@ Foam::PrimitivePatch<FaceList, PointField>::calcMeshData() const
         {
             if (markedPoints.insert(pointi, meshPoints.size()))
             {
-                meshPoints.append(pointi);
+                meshPoints.push_back(pointi);
             }
         }
     }
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchPointAddressing.C b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchPointAddressing.C
index 97add49b7a..66072a42db 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchPointAddressing.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchPointAddressing.C
@@ -82,7 +82,7 @@ Foam::PrimitivePatch<FaceList, PointField>::calcPointFaces() const
     {
         for (const label pointi : locFcs[facei])
         {
-            pointFcs[pointi].append(facei);
+            pointFcs[pointi].push_back(facei);
         }
     }