diff --git a/applications/test/bitSet1/Make/files b/applications/test/bitSet1/Make/files
index c87b831b38..7104798002 100644
--- a/applications/test/bitSet1/Make/files
+++ b/applications/test/bitSet1/Make/files
@@ -1,3 +1,3 @@
-Test-bitSet1.C
+Test-bitSet1.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-bitSet1
diff --git a/applications/test/bitSet1/Test-bitSet1.C b/applications/test/bitSet1/Test-bitSet1.cxx
similarity index 100%
rename from applications/test/bitSet1/Test-bitSet1.C
rename to applications/test/bitSet1/Test-bitSet1.cxx
diff --git a/applications/test/bitSet2/Test-bitSet2.cxx b/applications/test/bitSet2/Test-bitSet2.cxx
index 8f9f5d487e..6b0675b836 100644
--- a/applications/test/bitSet2/Test-bitSet2.cxx
+++ b/applications/test/bitSet2/Test-bitSet2.cxx
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -75,9 +75,9 @@ inline Ostream& info(const UList<bool>& bools)
     Info<< "size=" << bools.size()
         << " count=" << BitOps::count(bools)
         << " !count=" << BitOps::count(bools, false)
-        << " all:" << BitOps::all(bools)
-        << " any:" << BitOps::any(bools)
-        << " none:" << BitOps::none(bools) << nl;
+        << " all:" << bools.all()
+        << " any:" << bools.any()
+        << " none:" << bools.none() << nl;
 
     return Info;
 }
@@ -194,8 +194,10 @@ int main(int argc, char *argv[])
     {
         boolList bools = list1.values();
 
-        Info<<"===============" << nl;
-        Info<<"bools: " << flatOutput(bools) << nl;
+        Info<< "===============" << nl;
+        Info<< "bools: " << flatOutput(bools) << nl;
+        Info<< "    ";
+        info(bools);
 
         for (int i : { -10, 0, 8, 15, 32})
         {
@@ -238,17 +240,18 @@ int main(int argc, char *argv[])
     }
 
     #ifdef TEST_SFINAE
+    // This should fail to compile:
     {
         labelList labels = list1.toc();
         if (labels.test(0))
         {
-            Info<<"no" << endl;
+            Info<< "no" << endl;
         }
 
         List<double*> ptrs(10, nullptr);
         if (ptrs.get(0))
         {
-            Info<<"no" << endl;
+            Info<< "no" << endl;
         }
     }
     #endif
diff --git a/applications/test/boolList/Make/files b/applications/test/boolList/Make/files
index 9cbdcc0808..cde3a1614a 100644
--- a/applications/test/boolList/Make/files
+++ b/applications/test/boolList/Make/files
@@ -1,3 +1,3 @@
-Test-boolList.C
+Test-boolList.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-boolList
diff --git a/applications/test/boolList/Test-boolList.C b/applications/test/boolList/Test-boolList.cxx
similarity index 96%
rename from applications/test/boolList/Test-boolList.C
rename to applications/test/boolList/Test-boolList.cxx
index a55fe67a9b..36b96440a8 100644
--- a/applications/test/boolList/Test-boolList.C
+++ b/applications/test/boolList/Test-boolList.cxx
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020-2022 OpenCFD Ltd.
+    Copyright (C) 2020-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -71,9 +71,9 @@ inline Ostream& info(const UList<bool>& bools)
     Info<< "size=" << bools.size()
         << " count=" << BitOps::count(bools)
         << " !count=" << BitOps::count(bools, false)
-        << " all:" << BitOps::all(bools)
-        << " any:" << BitOps::any(bools)
-        << " none:" << BitOps::none(bools) << nl;
+        << " all:" << bools.all()
+        << " any:" << bools.any()
+        << " none:" << bools.none() << nl;
 
     return Info;
 }
diff --git a/src/OpenFOAM/containers/Bits/BitOps/BitOps.C b/src/OpenFOAM/containers/Bits/BitOps/BitOps.C
index 83f052543c..1e0fbaf938 100644
--- a/src/OpenFOAM/containers/Bits/BitOps/BitOps.C
+++ b/src/OpenFOAM/containers/Bits/BitOps/BitOps.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2023 OpenCFD Ltd.
+    Copyright (C) 2018-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -33,6 +33,12 @@ License
 
 // * * * * * * * * * * * * * * * * * BitOps  * * * * * * * * * * * * * * * * //
 
+unsigned int Foam::BitOps::count(const bitSet& bitset, const bool on)
+{
+    return bitset.count(on);
+}
+
+
 // See bitSet::setMany for original implementation
 void Foam::BitOps::set(List<bool>& bools, const labelUList& locations)
 {
diff --git a/src/OpenFOAM/containers/Bits/BitOps/BitOps.H b/src/OpenFOAM/containers/Bits/BitOps/BitOps.H
index fb0e1688fb..aa3b8edea2 100644
--- a/src/OpenFOAM/containers/Bits/BitOps/BitOps.H
+++ b/src/OpenFOAM/containers/Bits/BitOps/BitOps.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2018-2023 OpenCFD Ltd.
+    Copyright (C) 2018-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -77,26 +77,17 @@ inline unsigned int count(const UList<bool>& bools, const bool val=true)
     return std::count(bools.begin(), bools.end(), val);
 }
 
-//- True if all entries are 'true' or if the set is empty.
+//- True if all entries are 'true' or if the list is empty.
 //  For compatibility with bitSet::all()
-inline bool all(const UList<bool>& bools)
-{
-    return std::all_of(bools.begin(), bools.end(), identityOp());
-}
+inline bool all(const UList<bool>& bools) { return bools.all(); }
 
 //- True if any entries are 'true'.
 //  For compatibility with bitSet::any()
-inline bool any(const UList<bool>& bools)
-{
-    return std::any_of(bools.begin(), bools.end(), identityOp());
-}
+inline bool any(const UList<bool>& bools) { return bools.any(); }
 
 //- True if no entries are 'true'.
 //  For compatibility with bitSet::none()
-inline bool none(const UList<bool>& bools)
-{
-    return std::none_of(bools.begin(), bools.end(), identityOp());
-}
+inline bool none(const UList<bool>& bools) { return bools.none(); }
 
 
 //- Set the listed locations (assign 'true').
@@ -150,6 +141,10 @@ List<bool> select(const label n, const labelUList& locations);
 //  \return a List of bools
 List<bool> select(const labelUList& locations);
 
+//- Forward to bitSet::count()
+unsigned int count(const bitSet& bitset, const bool on=true);
+
+
 //- Return the (sorted) values corresponding to 'true' entries.
 //  Similar to bitSet::toc()
 //
@@ -292,13 +287,13 @@ struct bitInfo
     constexpr bitInfo() noexcept : value(0) {}
 
     //- Value construct
-    explicit bitInfo(UIntType val) : value(val) {}
+    explicit bitInfo(UIntType val) noexcept : value(val) {}
 
     //- Conversion to base type
-    operator UIntType () const { return value; }
+    operator UIntType () const noexcept { return value; }
 
     //- Conversion to base type
-    operator UIntType& () { return value; }
+    operator UIntType& () noexcept { return value; }
 };
 
 } // End namespace BitOps
diff --git a/src/OpenFOAM/containers/Lists/List/UList.H b/src/OpenFOAM/containers/Lists/List/UList.H
index a446eca351..15418892d2 100644
--- a/src/OpenFOAM/containers/Lists/List/UList.H
+++ b/src/OpenFOAM/containers/Lists/List/UList.H
@@ -565,11 +565,38 @@ public:
 
     // Special Methods
 
+        //- True if all entries are 'true' or if the list is empty.
+        //  \note Method name compatibility with bitSet
+        template<class TypeT = T>
+        std::enable_if_t<std::is_same_v<bool, std::remove_cv_t<TypeT>>, bool>
+        inline all() const
+        {
+            return !contains(false);
+        }
+
+        //- True if any entries are 'true'.
+        //  \note Method name compatibility with bitSet
+        template<class TypeT = T>
+        std::enable_if_t<std::is_same_v<bool, std::remove_cv_t<TypeT>>, bool>
+        inline any() const
+        {
+            return contains(true);
+        }
+
+        //- True if no entries are 'true'.
+        //  \note Method name compatibility with bitSet
+        template<class TypeT = T>
+        std::enable_if_t<std::is_same_v<bool, std::remove_cv_t<TypeT>>, bool>
+        inline none() const
+        {
+            return !contains(true);
+        }
+
         //- Test \c bool value at specified position,
         //- always false for out-of-range access.
         //  \note Method name compatibility with bitSet, HashSet
         template<class TypeT = T>
-        std::enable_if_t<std::is_same_v<bool, TypeT>, bool>
+        std::enable_if_t<std::is_same_v<bool, std::remove_cv_t<TypeT>>, bool>
         inline test(const label i) const
         {
             return (i >= 0 && i < size_ && v_[i]);
@@ -579,7 +606,7 @@ public:
         //- always false for out-of-range access.
         //  \note Method name compatibility with bitSet
         template<class TypeT = T>
-        std::enable_if_t<std::is_same_v<bool, TypeT>, bool>
+        std::enable_if_t<std::is_same_v<bool, std::remove_cv_t<TypeT>>, bool>
         inline get(const label i) const
         {
             return (i >= 0 && i < size_ && v_[i]);
diff --git a/src/OpenFOAM/containers/Lists/List/UListI.H b/src/OpenFOAM/containers/Lists/List/UListI.H
index 9e544cbfcf..d90e72e74e 100644
--- a/src/OpenFOAM/containers/Lists/List/UListI.H
+++ b/src/OpenFOAM/containers/Lists/List/UListI.H
@@ -348,29 +348,25 @@ inline void Foam::UList<T>::operator=(const T& val)
 }
 
 
-namespace Foam
-{
-    // Template specialization for bool
-    template<>
-    inline const bool& Foam::UList<bool>::operator[](const label i) const
-    {
-        // Lazy evaluation - return false for out-of-range
-        if (i >= 0 && i < size_)
-        {
-            return v_[i];
-        }
-
-        return Foam::pTraits<bool>::zero;
-    }
-} // End namespace Foam
-
-
 template<class T>
 inline T& Foam::UList<T>::operator[](const label i)
 {
-    #ifdef FULLDEBUG
-    checkIndex(i);
-    #endif
+    if constexpr (std::is_same_v<bool, std::remove_cv_t<T>>)
+    {
+        // Lazy evaluation - return false for out-of-range
+        // Note: strictly speaking should not be modifiable but we cannot
+        // alway control which signature (const or non-const) is called
+        if (i < 0 || i >= size_)
+        {
+            return const_cast<bool&>(Foam::pTraits<bool>::null());
+        }
+    }
+    else
+    {
+        #ifdef FULLDEBUG
+        checkIndex(i);
+        #endif
+    }
     return v_[i];
 }
 
@@ -378,9 +374,20 @@ inline T& Foam::UList<T>::operator[](const label i)
 template<class T>
 inline const T& Foam::UList<T>::operator[](const label i) const
 {
-    #ifdef FULLDEBUG
-    checkIndex(i);
-    #endif
+    if constexpr (std::is_same_v<bool, std::remove_cv_t<T>>)
+    {
+        // Lazy evaluation - return false for out-of-range
+        if (i < 0 || i >= size_)
+        {
+            return Foam::pTraits<bool>::null();
+        }
+    }
+    else
+    {
+        #ifdef FULLDEBUG
+        checkIndex(i);
+        #endif
+    }
     return v_[i];
 }
 
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
index 73b941d3a9..5343eb6384 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
@@ -658,6 +658,18 @@ inline void identity(labelUList& map, label start = 0)
 }
 
 
+//- Count the occurrences of the given element.
+//  When start is specified, any occurrences before start are ignored.
+//  Like std::count but works with list indexing
+template<class ListType>
+label count
+(
+    const ListType& input,
+    typename ListType::const_reference val,
+    const label start=0
+);
+
+
 //- Count the number of matching entries.
 //  When start is specified, any occurrences before start are ignored.
 //  Linear search.
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
index a58efd291e..f743feaf0e 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
@@ -1154,6 +1154,33 @@ bool Foam::ListOps::equal
 }
 
 
+template<class ListType>
+Foam::label Foam::ListOps::count
+(
+    const ListType& input,
+    typename ListType::const_reference val,
+    const label start
+)
+{
+    label num = 0;
+
+    const label len = input.size();
+
+    if (start >= 0)
+    {
+        for (label i = start; i < len; ++i)
+        {
+            if (val == input[i])
+            {
+                ++num;
+            }
+        }
+    }
+
+    return num;
+}
+
+
 template<class ListType, class UnaryPredicate>
 Foam::label Foam::ListOps::count_if
 (
diff --git a/src/OpenFOAM/primitives/bools/bool/bool.C b/src/OpenFOAM/primitives/bools/bool/bool.C
index cb796a5371..09770db906 100644
--- a/src/OpenFOAM/primitives/bools/bool/bool.C
+++ b/src/OpenFOAM/primitives/bools/bool/bool.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2021 OpenCFD Ltd.
+    Copyright (C) 2018-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -38,6 +38,16 @@ const char* const Foam::pTraits<bool>::componentNames[] = { "" };
 
 const bool Foam::pTraits<bool>::zero = false;
 const bool Foam::pTraits<bool>::one = true;
+bool Foam::pTraits<bool>::dummy = false;
+
+
+// * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
+
+const bool& Foam::pTraits<bool>::null() noexcept
+{
+    dummy = false;
+    return dummy;
+}
 
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
diff --git a/src/OpenFOAM/primitives/bools/bool/bool.H b/src/OpenFOAM/primitives/bools/bool/bool.H
index 090fae4137..b766903d63 100644
--- a/src/OpenFOAM/primitives/bools/bool/bool.H
+++ b/src/OpenFOAM/primitives/bools/bool/bool.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2025 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -97,6 +97,10 @@ public:
         static const char* const componentNames[];
         static const bool zero;
         static const bool one;
+        static bool dummy;  //!< Dummy for return reference
+
+        //- Return reference to a (false) dummy value
+        static const bool& null() noexcept;
 
 
     // Constructors
diff --git a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
index ba67ac8902..75a30f2f29 100644
--- a/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
+++ b/src/parallel/decompose/decompositionMethods/decompositionMethod/decompositionMethod.C
@@ -512,7 +512,7 @@ Foam::labelList Foam::decompositionMethod::decompose
     const bool hasUnblocked =
         returnReduceOr
         (
-            !blockedFace.empty() && !BitOps::all(blockedFace)
+            !blockedFace.empty() && !blockedFace.all()
         );