diff --git a/applications/test/IndirectList/Test-IndirectList.C b/applications/test/IndirectList/Test-IndirectList.C
index 2f3a2e45d4..27736a2cd6 100644
--- a/applications/test/IndirectList/Test-IndirectList.C
+++ b/applications/test/IndirectList/Test-IndirectList.C
@@ -106,6 +106,18 @@ int main(int argc, char *argv[])
         testFind(val, idl1);
     }
 
+    {
+        auto iter = idl1.cbegin();
+        const auto endIter = idl1.cend();
+
+        while (iter != endIter)
+        {
+            // No post-fix increment:
+            Info<< *iter << nl;
+            ++iter;
+        }
+    }
+
     inplaceReverseList(addresses);
 
     idl1.addressing() = std::move(addresses);
diff --git a/src/OpenFOAM/containers/Bits/PackedList/PackedList.H b/src/OpenFOAM/containers/Bits/PackedList/PackedList.H
index 23401256b6..1cb1395ad2 100644
--- a/src/OpenFOAM/containers/Bits/PackedList/PackedList.H
+++ b/src/OpenFOAM/containers/Bits/PackedList/PackedList.H
@@ -89,8 +89,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef PackedList_H
-#define PackedList_H
+#ifndef Foam_PackedList_H
+#define Foam_PackedList_H
 
 #include "BitOps.H"
 #include "labelList.H"
@@ -362,10 +362,9 @@ public:
         //- Currently identical to resize. Subject to future change (Oct-2021)
         inline void resize_nocopy(const label numElem);
 
-        //- Reserve allocation space for at least this size.
+        //- Reserve allocation space for at least this size
+        //- (uses a size doubling strategy).
         //  Never shrinks the allocated size.
-        //  The list size is adjusted as per DynamicList with
-        //  SizeInc=0, SizeMult=2, SizeDiv=1
         inline void reserve(const label numElem);
 
         //- Clear the list, i.e. set addressable size to zero.
diff --git a/src/OpenFOAM/containers/IndirectLists/IndirectListBase/IndirectListBase.H b/src/OpenFOAM/containers/IndirectLists/IndirectListBase/IndirectListBase.H
index ae54058005..2c01a2c75c 100644
--- a/src/OpenFOAM/containers/IndirectLists/IndirectListBase/IndirectListBase.H
+++ b/src/OpenFOAM/containers/IndirectLists/IndirectListBase/IndirectListBase.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -39,8 +39,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef IndirectListBase_H
-#define IndirectListBase_H
+#ifndef Foam_IndirectListBase_H
+#define Foam_IndirectListBase_H
 
 #include "List.H"
 
@@ -242,9 +242,11 @@ public:
     // Iterators
 
         //- A non-const iterator for an indirect list
+        //  Only supports forward prefix increment, since the addressing
+        //  may/may not support postfix or decrement.
         class iterator
         {
-            typename UList<T>::pointer data_;
+            T* begin_;
             typename addressing_type::const_iterator iter_;
 
         public:
@@ -258,17 +260,14 @@ public:
             iterator
             (
                 UList<T>& list,
-                typename addressing_type::const_iterator baseIter
+                typename addressing_type::const_iterator addrIter
             )
             :
-                data_(list.begin()),
-                iter_(baseIter)
+                begin_(list.data()),
+                iter_(addrIter)
             {}
 
-            reference operator*() const
-            {
-                return data_[*iter_];
-            }
+            reference operator*() const { return *(begin_ + *iter_); }
 
             iterator& operator++()
             {
@@ -276,12 +275,12 @@ public:
                 return *this;
             }
 
-            bool operator==(iterator& rhs) const
+            bool operator==(const iterator& rhs) const
             {
-                return iter_ == rhs.iter_;
+                return (iter_ == rhs.iter_);
             }
 
-            bool operator!=(iterator& rhs) const
+            bool operator!=(const iterator& rhs) const
             {
                 return (iter_ != rhs.iter_);
             }
@@ -289,9 +288,11 @@ public:
 
 
         //- A const iterator for an indirect list
+        //  Only supports forward prefix increment, since the addressing
+        //  may/may not support postfix or decrement.
         class const_iterator
         {
-            typename UList<T>::const_pointer data_;
+            const T* begin_;
             typename addressing_type::const_iterator iter_;
 
         public:
@@ -305,17 +306,14 @@ public:
             const_iterator
             (
                 const UList<T>& list,
-                typename addressing_type::const_iterator baseIter
+                typename addressing_type::const_iterator addrIter
             )
             :
-                data_(list.begin()),
-                iter_(baseIter)
+                begin_(list.cdata()),
+                iter_(addrIter)
             {}
 
-            reference operator*() const
-            {
-                return data_[*iter_];
-            }
+            reference operator*() const { return *(begin_ + *iter_); }
 
             const_iterator& operator++()
             {
@@ -323,14 +321,14 @@ public:
                 return *this;
             }
 
-            bool operator==(const_iterator& rhs) const
+            bool operator==(const const_iterator& rhs) const
             {
-                return iter_ == rhs.iter_;
+                return (iter_ == rhs.iter_);
             }
 
-            bool operator!=(const_iterator& rhs) const
+            bool operator!=(const const_iterator& rhs) const
             {
-                return iter_ != rhs.iter_;
+                return (iter_ != rhs.iter_);
             }
         };
 
@@ -364,17 +362,11 @@ public:
             return const_iterator(values_, addr_.cend());
         }
 
-        //- Return a const_iterator at end of list
-        inline const_iterator begin() const
-        {
-            return cbegin();
-        }
+        //- Return a const_iterator at begin of list
+        const_iterator begin() const { return cbegin(); }
 
         //- Return a const_iterator at end of list
-        inline const_iterator end() const
-        {
-            return cend();
-        }
+        const_iterator end() const { return cend(); }
 
 
     // Writing
diff --git a/src/OpenFOAM/containers/Lists/DynamicList/DynamicList.H b/src/OpenFOAM/containers/Lists/DynamicList/DynamicList.H
index c97645e21f..57919c75bf 100644
--- a/src/OpenFOAM/containers/Lists/DynamicList/DynamicList.H
+++ b/src/OpenFOAM/containers/Lists/DynamicList/DynamicList.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -42,8 +42,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef DynamicList_H
-#define DynamicList_H
+#ifndef Foam_DynamicList_H
+#define Foam_DynamicList_H
 
 #include "List.H"
 
@@ -154,9 +154,6 @@ public:
         //- Move construct from List
         inline DynamicList(List<T>&& lst);
 
-        //- Move construct from SortableList
-        DynamicList(SortableList<T>&& lst);
-
         //- Construct from Istream. Size set to size of list read.
         explicit DynamicList(Istream& is);
 
@@ -259,47 +256,32 @@ public:
             template<int AnySizeMin>
             inline void transfer(DynamicList<T, AnySizeMin>& list);
 
-            //- Transfer contents  of the argument SortableList into this.
-            inline void transfer(SortableList<T>& list);
-
-            //- Append an element to the end of this list.
-            inline DynamicList<T, SizeMin>& append(const T& val);
+            //- Copy append an element to the end of this list.
+            inline void append(const T& val);
 
             //- Move append an element
-            inline DynamicList<T, SizeMin>& append(T&& val);
+            inline void append(T&& val);
 
             //- Append another list to the end of this list.
-            inline DynamicList<T, SizeMin>& append(const UList<T>& lst);
+            inline void append(const UList<T>& lst);
 
             //- Append a FixedList to the end of this list.
             template<unsigned N>
-            inline DynamicList<T, SizeMin>&
-            append(const FixedList<T, N>& lst);
+            inline void append(const FixedList<T, N>& lst);
 
             //- Append an initializer list at the end of this list.
-            inline DynamicList<T, SizeMin>&
-            append(std::initializer_list<T> lst);
+            inline void append(std::initializer_list<T> lst);
 
             //- Append a IndirectList at the end of this list
             template<class Addr>
-            inline DynamicList<T, SizeMin>&
-            append(const IndirectListBase<T, Addr>& lst);
+            inline void append(const IndirectListBase<T, Addr>& lst);
 
             //- Move append list
-            inline DynamicList<T, SizeMin>& append(List<T>&& lst);
-
-            //- Move append list
-            inline DynamicList<T, SizeMin>&
-            append(DynamicList<T, SizeMin>&& lst);
+            inline void append(List<T>&& lst);
 
             //- Move append list
             template<int AnySizeMin>
-            inline DynamicList<T, SizeMin>&
-            append(DynamicList<T, AnySizeMin>&& lst);
-
-            //- Move append list
-            inline DynamicList<T, SizeMin>&
-            append(SortableList<T>&& lst);
+            inline void append(DynamicList<T, AnySizeMin>&& list);
 
             //- Append an element if not already in the list.
             //  \return the change in list length
@@ -377,9 +359,6 @@ public:
             template<int AnySizeMin>
             inline void operator=(DynamicList<T, AnySizeMin>&& lst);
 
-            //- Move assignment
-            inline void operator=(SortableList<T>&& lst);
-
 
     // Reading/writing
 
diff --git a/src/OpenFOAM/containers/Lists/DynamicList/DynamicListI.H b/src/OpenFOAM/containers/Lists/DynamicList/DynamicListI.H
index 972317b735..ee52e49b84 100644
--- a/src/OpenFOAM/containers/Lists/DynamicList/DynamicListI.H
+++ b/src/OpenFOAM/containers/Lists/DynamicList/DynamicListI.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -493,21 +493,7 @@ Foam::DynamicList<T, SizeMin>::transfer
 
 
 template<class T, int SizeMin>
-inline void
-Foam::DynamicList<T, SizeMin>::transfer
-(
-    SortableList<T>& list
-)
-{
-    list.shrink();  // Shrink away sort indices
-    capacity_ = list.size(); // Capacity after transfer == list size
-    List<T>::transfer(list);
-}
-
-
-template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     const T& val
 )
@@ -516,13 +502,11 @@ Foam::DynamicList<T, SizeMin>::append
     resize(idx + 1);
 
     this->operator[](idx) = val;  // copy element
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     T&& val
 )
@@ -531,13 +515,11 @@ Foam::DynamicList<T, SizeMin>::append
     resize(idx + 1);
 
     this->operator[](idx) = std::move(val);  // move assign element
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     const UList<T>& lst
 )
@@ -556,14 +538,12 @@ Foam::DynamicList<T, SizeMin>::append
     {
         this->operator[](idx++) = val;  // copy element
     }
-    return *this;
 }
 
 
 template<class T, int SizeMin>
 template<unsigned N>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     const FixedList<T, N>& lst
 )
@@ -575,13 +555,11 @@ Foam::DynamicList<T, SizeMin>::append
     {
         this->operator[](idx++) = val;  // copy element
     }
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     std::initializer_list<T> lst
 )
@@ -593,14 +571,12 @@ Foam::DynamicList<T, SizeMin>::append
     {
         this->operator[](idx++) = val;  // copy element
     }
-    return *this;
 }
 
 
 template<class T, int SizeMin>
 template<class Addr>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     const IndirectListBase<T, Addr>& lst
 )
@@ -614,13 +590,11 @@ Foam::DynamicList<T, SizeMin>::append
     {
         this->operator[](idx++) = lst[i];  // copy element
     }
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
     List<T>&& list
 )
@@ -641,47 +615,18 @@ Foam::DynamicList<T, SizeMin>::append
     }
 
     list.clear();
-    return *this;
-}
-
-
-template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
-(
-    DynamicList<T, SizeMin>&& lst
-)
-{
-    append(std::move(static_cast<List<T>&>(lst)));
-    lst.clearStorage();  // Ensure capacity=0
-    return *this;
 }
 
 
 template<class T, int SizeMin>
 template<int AnySizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
+inline void Foam::DynamicList<T, SizeMin>::append
 (
-    DynamicList<T, AnySizeMin>&& lst
+    DynamicList<T, AnySizeMin>&& list
 )
 {
-    append(std::move(static_cast<List<T>&>(lst)));
-    lst.clearStorage();  // Ensure capacity=0
-    return *this;
-}
-
-
-template<class T, int SizeMin>
-inline Foam::DynamicList<T, SizeMin>&
-Foam::DynamicList<T, SizeMin>::append
-(
-    SortableList<T>&& lst
-)
-{
-    lst.shrink();  // Shrink away sort indices
-    append(std::move(static_cast<List<T>&>(lst)));
-    return *this;
+    append(std::move(static_cast<List<T>&>(list)));
+    list.clearStorage();  // Ensure capacity=0
 }
 
 
@@ -939,15 +884,4 @@ inline void Foam::DynamicList<T, SizeMin>::operator=
 }
 
 
-template<class T, int SizeMin>
-inline void Foam::DynamicList<T, SizeMin>::operator=
-(
-    SortableList<T>&& lst
-)
-{
-    clear();
-    transfer(lst);
-}
-
-
 // ************************************************************************* //
diff --git a/src/OpenFOAM/containers/Lists/List/List.C b/src/OpenFOAM/containers/Lists/List/List.C
index d6bcf0cea1..0384aa013c 100644
--- a/src/OpenFOAM/containers/Lists/List/List.C
+++ b/src/OpenFOAM/containers/Lists/List/List.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -405,15 +405,6 @@ Foam::List<T>::List(DynamicList<T, SizeMin>&& list)
 }
 
 
-template<class T>
-Foam::List<T>::List(SortableList<T>&& list)
-:
-    UList<T>()
-{
-    transfer(list);
-}
-
-
 template<class T>
 Foam::List<T>::List(SLList<T>&& list)
 :
@@ -483,15 +474,6 @@ void Foam::List<T>::transfer(DynamicList<T, SizeMin>& list)
 }
 
 
-template<class T>
-void Foam::List<T>::transfer(SortableList<T>& list)
-{
-    // Shrink away the sort indices
-    list.shrink();
-    transfer(static_cast<List<T>&>(list));
-}
-
-
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
 template<class T>
@@ -638,13 +620,6 @@ void Foam::List<T>::operator=(DynamicList<T, SizeMin>&& list)
 }
 
 
-template<class T>
-void Foam::List<T>::operator=(SortableList<T>&& list)
-{
-    transfer(list);
-}
-
-
 template<class T>
 void Foam::List<T>::operator=(SLList<T>&& list)
 {
diff --git a/src/OpenFOAM/containers/Lists/List/List.H b/src/OpenFOAM/containers/Lists/List/List.H
index c300941d48..6bf34de25b 100644
--- a/src/OpenFOAM/containers/Lists/List/List.H
+++ b/src/OpenFOAM/containers/Lists/List/List.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -40,8 +40,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef List_H
-#define List_H
+#ifndef Foam_List_H
+#define Foam_List_H
 
 #include "autoPtr.H"
 #include "UList.H"
@@ -58,7 +58,6 @@ template<class T, unsigned N> class FixedList;
 template<class T, int SizeMin> class DynamicList;
 
 template<class T> class PtrList;
-template<class T> class SortableList;
 
 template<class T> Istream& operator>>(Istream& is, List<T>& list);
 
@@ -182,9 +181,6 @@ public:
         template<int SizeMin>
         List(DynamicList<T, SizeMin>&& list);
 
-        //- Move construct from SortableList
-        List(SortableList<T>&& list);
-
         //- Move construct from SLList
         List(SLList<T>&& list);
 
@@ -258,10 +254,6 @@ public:
             template<int SizeMin>
             void transfer(DynamicList<T, SizeMin>& list);
 
-            //- Transfer the contents of the argument List into this list
-            //- and annul the argument list
-            void transfer(SortableList<T>& list);
-
             //- Return subscript-checked element of UList and resizing the list
             //- if required.
             inline T& newElmt(const label i);
@@ -302,9 +294,6 @@ public:
         template<int SizeMin>
         void operator=(DynamicList<T, SizeMin>&& list);
 
-        //- Move assignment. Takes constant time.
-        void operator=(SortableList<T>&& list);
-
         //- Move assignment. Takes constant time
         void operator=(SLList<T>&& list);
 
diff --git a/src/OpenFOAM/containers/Lists/SortableList/SortableList.C b/src/OpenFOAM/containers/Lists/SortableList/SortableList.C
index 70cc75a575..28288a5bc0 100644
--- a/src/OpenFOAM/containers/Lists/SortableList/SortableList.C
+++ b/src/OpenFOAM/containers/Lists/SortableList/SortableList.C
@@ -105,7 +105,7 @@ inline Foam::SortableList<T>::SortableList(std::initializer_list<T> values)
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class T>
-void Foam::SortableList<T>::clear()
+inline void Foam::SortableList<T>::clear()
 {
     List<T>::clear();
     indices_.clear();
@@ -113,7 +113,7 @@ void Foam::SortableList<T>::clear()
 
 
 template<class T>
-Foam::List<T>& Foam::SortableList<T>::shrink()
+inline Foam::List<T>& Foam::SortableList<T>::shrink()
 {
     indices_.clear();
     return static_cast<List<T>&>(*this);
diff --git a/src/OpenFOAM/containers/Lists/SortableList/SortableList.H b/src/OpenFOAM/containers/Lists/SortableList/SortableList.H
index 8a0ce95f02..3009fbeeef 100644
--- a/src/OpenFOAM/containers/Lists/SortableList/SortableList.H
+++ b/src/OpenFOAM/containers/Lists/SortableList/SortableList.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2021 OpenCFD Ltd.
+    Copyright (C) 2017-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -43,8 +43,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef SortableList_H
-#define SortableList_H
+#ifndef Foam_SortableList_H
+#define Foam_SortableList_H
 
 #include "labelList.H"
 
@@ -106,22 +106,22 @@ public:
     // Member Functions
 
         //- Return the list of sorted indices. Updated every sort
-        const labelList& indices() const
+        const labelList& indices() const noexcept
         {
             return indices_;
         }
 
         //- Return non-const access to the sorted indices. Updated every sort
-        labelList& indices()
+        labelList& indices() noexcept
         {
             return indices_;
         }
 
         //- Clear the list and the indices
-        void clear();
+        inline void clear();
 
         //- Clear the indices and return a reference to the underlying List
-        List<T>& shrink();
+        inline List<T>& shrink();
 
         //- Forward (stable) sort the list (if changed after construction).
         //  Resizes the indices as required
@@ -163,15 +163,7 @@ public:
 };
 
 
-// * * * * * * * * * * * * * * * Global Functions  * * * * * * * * * * * * * //
-
-// Exchange contents of lists - see SortableList::swap().
-template<class T>
-inline void Swap(SortableList<T>& a, SortableList<T>& b)
-{
-    a.swap(b);
-}
-
+// Note: uses default Foam::Swap (move construct/assignment)
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
diff --git a/src/OpenFOAM/fields/Fields/DynamicField/DynamicField.H b/src/OpenFOAM/fields/Fields/DynamicField/DynamicField.H
index 1293335420..1ae483354c 100644
--- a/src/OpenFOAM/fields/Fields/DynamicField/DynamicField.H
+++ b/src/OpenFOAM/fields/Fields/DynamicField/DynamicField.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,8 +35,8 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef DynamicField_H
-#define DynamicField_H
+#ifndef Foam_DynamicField_H
+#define Foam_DynamicField_H
 
 #include "Field.H"
 #include "DynamicList.H"
@@ -283,14 +283,13 @@ public:
         inline void transfer(DynamicField<T, AnySizeMin>& list);
 
         //- Append an element at the end of the list
-        inline DynamicField<T, SizeMin>& append(const T& val);
+        inline void append(const T& val);
 
         //- Move append an element
-        inline DynamicField<T, SizeMin>& append(T&& val);
+        inline void append(T&& val);
 
         //- Append a List at the end of this list
-        inline DynamicField<T, SizeMin>&
-        append(const UList<T>& list);
+        inline void append(const UList<T>& list);
 
         //- Remove and return the top element
         inline T remove();
diff --git a/src/OpenFOAM/fields/Fields/DynamicField/DynamicFieldI.H b/src/OpenFOAM/fields/Fields/DynamicField/DynamicFieldI.H
index 7a3da86416..bfca3759ca 100644
--- a/src/OpenFOAM/fields/Fields/DynamicField/DynamicFieldI.H
+++ b/src/OpenFOAM/fields/Fields/DynamicField/DynamicFieldI.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -582,8 +582,7 @@ inline void Foam::DynamicField<T, SizeMin>::transfer
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicField<T, SizeMin>&
-Foam::DynamicField<T, SizeMin>::append
+inline void Foam::DynamicField<T, SizeMin>::append
 (
     const T& val
 )
@@ -592,13 +591,11 @@ Foam::DynamicField<T, SizeMin>::append
     resize(idx + 1);
 
     this->operator[](idx) = val;  // copy element
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicField<T, SizeMin>&
-Foam::DynamicField<T, SizeMin>::append
+inline void Foam::DynamicField<T, SizeMin>::append
 (
     T&& val
 )
@@ -607,13 +604,11 @@ Foam::DynamicField<T, SizeMin>::append
     resize(idx + 1);
 
     this->operator[](idx) = std::move(val);  // move assign element
-    return *this;
 }
 
 
 template<class T, int SizeMin>
-inline Foam::DynamicField<T, SizeMin>&
-Foam::DynamicField<T, SizeMin>::append
+inline void Foam::DynamicField<T, SizeMin>::append
 (
     const UList<T>& list
 )
@@ -632,7 +627,6 @@ Foam::DynamicField<T, SizeMin>::append
     {
         this->operator[](idx++) = val;  // copy element
     }
-    return *this;
 }