diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 52d187f..8e06101 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v4.5.0
+  rev: v6.0.0
   hooks:
   - id: check-yaml
   - id: end-of-file-fixer
@@ -11,7 +11,7 @@ repos:
 
 
 - repo: https://github.com/pre-commit/mirrors-clang-format
-  rev: v17.0.6
+  rev: v22.1.3
   hooks:
   - id: clang-format
     types_or: [c++, c, cuda]
diff --git a/include/boost/heap/binomial_heap.hpp b/include/boost/heap/binomial_heap.hpp
index 873007a..87798e4 100644
--- a/include/boost/heap/binomial_heap.hpp
+++ b/include/boost/heap/binomial_heap.hpp
@@ -242,6 +242,8 @@ class binomial_heap :
     /// \copydoc boost::heap::priority_queue::operator=(priority_queue const &)
     binomial_heap& operator=( binomial_heap const& rhs )
     {
+        if ( this == &rhs )
+            return *this;
         clear();
         size_holder::set_size( rhs.get_size() );
         static_cast< super_t& >( *this ) = rhs;
@@ -400,7 +402,7 @@ class binomial_heap :
         size_holder::decrement();
 
         if ( element->child_count() ) {
-            size_type sz = ( 1 << element->child_count() ) - 1;
+            size_type sz = ( size_type( 1 ) << element->child_count() ) - 1;
 
             binomial_heap children( value_comp(), element->children, sz );
             if ( trees.empty() ) {
@@ -543,7 +545,7 @@ class binomial_heap :
         rhs.set_size( 0 );
         rhs.top_element = nullptr;
 
-        super_t::set_stability_count( ( std::max )( super_t::get_stability_count(), rhs.get_stability_count() ) );
+        super_t::set_stability_count( (std::max)( super_t::get_stability_count(), rhs.get_stability_count() ) );
         rhs.set_stability_count( 0 );
     }
 
diff --git a/include/boost/heap/d_ary_heap.hpp b/include/boost/heap/d_ary_heap.hpp
index dff1f9c..470e91e 100644
--- a/include/boost/heap/d_ary_heap.hpp
+++ b/include/boost/heap/d_ary_heap.hpp
@@ -345,7 +345,7 @@ class d_ary_heap : private make_heap_base< T, BoundArgs, false >::type
     size_type last_child_index( size_type index ) const
     {
         const size_t    first_index = first_child_index( index );
-        const size_type last_index  = ( std::min )( first_index + D - 1, size() - 1 );
+        const size_type last_index  = (std::min)( first_index + D - 1, size() - 1 );
 
         return last_index;
     }
diff --git a/include/boost/heap/detail/ilog2.hpp b/include/boost/heap/detail/ilog2.hpp
index 3dc4f1e..2870d04 100644
--- a/include/boost/heap/detail/ilog2.hpp
+++ b/include/boost/heap/detail/ilog2.hpp
@@ -56,6 +56,6 @@ IntType log2( IntType value )
     return fn( value );
 }
 
-}}     // namespace boost::heap
+}} // namespace boost::heap
 
 #endif /* BOOST_HEAP_DETAIL_ILOG2_HPP */
diff --git a/include/boost/heap/detail/mutable_heap.hpp b/include/boost/heap/detail/mutable_heap.hpp
index cccfb47..c5d309c 100644
--- a/include/boost/heap/detail/mutable_heap.hpp
+++ b/include/boost/heap/detail/mutable_heap.hpp
@@ -354,7 +354,9 @@ class priority_queue_mutable_wrapper
     template < class... Args >
     handle_type emplace( Args&&... args )
     {
-        objects.push_front( std::make_pair( std::forward< Args >( args )..., 0 ) );
+        objects.emplace_front( std::piecewise_construct,
+                               std::forward_as_tuple( std::forward< Args >( args )... ),
+                               std::forward_as_tuple( 0 ) );
         list_iterator ret = objects.begin();
         q_.push( ret );
         return handle_type( ret );
@@ -520,6 +522,6 @@ class priority_queue_mutable_wrapper
 };
 
 
-}}}    // namespace boost::heap::detail
+}}} // namespace boost::heap::detail
 
 #endif /* BOOST_HEAP_DETAIL_MUTABLE_HEAP_HPP */
diff --git a/include/boost/heap/detail/ordered_adaptor_iterator.hpp b/include/boost/heap/detail/ordered_adaptor_iterator.hpp
index 4e88bc0..d84b127 100644
--- a/include/boost/heap/detail/ordered_adaptor_iterator.hpp
+++ b/include/boost/heap/detail/ordered_adaptor_iterator.hpp
@@ -131,6 +131,6 @@ class ordered_adaptor_iterator :
 };
 
 
-}}}    // namespace boost::heap::detail
+}}} // namespace boost::heap::detail
 
 #endif /* BOOST_HEAP_DETAIL_ORDERED_ADAPTOR_ITERATOR_HPP */
diff --git a/include/boost/heap/detail/stable_heap.hpp b/include/boost/heap/detail/stable_heap.hpp
index 25ff88e..2272068 100644
--- a/include/boost/heap/detail/stable_heap.hpp
+++ b/include/boost/heap/detail/stable_heap.hpp
@@ -380,18 +380,18 @@ struct heap_base< T, Cmp, constant_time_size, StabilityCounterType, true > :
 
     internal_type make_node( T const& val )
     {
-        stability_counter_type count = ++counter_;
-        if ( counter_ == ( std::numeric_limits< stability_counter_type >::max )() )
+        if ( counter_ == ( std::numeric_limits< stability_counter_type >::max )() - 1 )
             BOOST_THROW_EXCEPTION( std::runtime_error( "boost::heap counter overflow" ) );
+        stability_counter_type count = ++counter_;
         return internal_type( count, val );
     }
 
     template < class... Args >
     internal_type make_node( Args&&... args )
     {
-        stability_counter_type count = ++counter_;
-        if ( counter_ == ( std::numeric_limits< stability_counter_type >::max )() )
+        if ( counter_ == ( std::numeric_limits< stability_counter_type >::max )() - 1 )
             BOOST_THROW_EXCEPTION( std::runtime_error( "boost::heap counter overflow" ) );
+        stability_counter_type count = ++counter_;
         return internal_type( count, std::forward< Args >( args )... );
     }
 
@@ -563,6 +563,6 @@ struct extract_allocator_types
 };
 
 
-}}}    // namespace boost::heap::detail
+}}} // namespace boost::heap::detail
 
 #endif /* BOOST_HEAP_DETAIL_STABLE_HEAP_HPP */
diff --git a/include/boost/heap/detail/tree_iterator.hpp b/include/boost/heap/detail/tree_iterator.hpp
index 2988161..aadbdba 100644
--- a/include/boost/heap/detail/tree_iterator.hpp
+++ b/include/boost/heap/detail/tree_iterator.hpp
@@ -14,6 +14,7 @@
 
 #include <boost/core/allocator_access.hpp>
 #include <boost/iterator/iterator_adaptor.hpp>
+#include <boost/static_assert.hpp>
 #include <boost/type_traits/conditional.hpp>
 #include <queue>
 
@@ -343,6 +344,6 @@ class recursive_tree_iterator :
 };
 
 
-}}}    // namespace boost::heap::detail
+}}} // namespace boost::heap::detail
 
 #endif /* BOOST_HEAP_DETAIL_TREE_ITERATOR_HPP */
diff --git a/include/boost/heap/fibonacci_heap.hpp b/include/boost/heap/fibonacci_heap.hpp
index 7ca9ae6..7b37790 100644
--- a/include/boost/heap/fibonacci_heap.hpp
+++ b/include/boost/heap/fibonacci_heap.hpp
@@ -260,6 +260,8 @@ class fibonacci_heap :
     /// \copydoc boost::heap::priority_queue::operator=(priority_queue const &)
     fibonacci_heap& operator=( fibonacci_heap const& rhs )
     {
+        if ( this == &rhs )
+            return *this;
         clear();
         size_holder::set_size( rhs.size() );
         static_cast< super_t& >( *this ) = rhs;
@@ -591,7 +593,7 @@ class fibonacci_heap :
         rhs.top_element = nullptr;
         rhs.set_size( 0 );
 
-        super_t::set_stability_count( ( std::max )( super_t::get_stability_count(), rhs.get_stability_count() ) );
+        super_t::set_stability_count( (std::max)( super_t::get_stability_count(), rhs.get_stability_count() ) );
         rhs.set_stability_count( 0 );
     }
 
@@ -699,8 +701,13 @@ class fibonacci_heap :
         if ( roots.empty() )
             return;
 
-        static const size_type               max_log2 = sizeof( size_type ) * 8;
-        std::array< node_pointer, max_log2 > aux {};
+        // The maximum degree of any node in a Fibonacci heap with N elements is
+        // floor(log_phi(N)) where phi = (1+sqrt(5))/2 ~ 1.618.  Since
+        // log_phi(N) < 1.4405 * log2(N), a safe upper bound on the degree for a
+        // size_type of B bits is ceil(1.4405 * B) + 2.  We compute a conservative
+        // compile-time constant that is always large enough.
+        constexpr size_type                    max_degree = sizeof( size_type ) * 12 + 4;
+        std::array< node_pointer, max_degree > aux {};
 
         node_list_iterator it = roots.begin();
         top_element           = static_cast< node_pointer >( &*it );
@@ -709,6 +716,7 @@ class fibonacci_heap :
             node_pointer n = static_cast< node_pointer >( &*it );
             ++it;
             size_type node_rank = n->child_count();
+            BOOST_ASSERT( node_rank < max_degree );
 
             if ( aux[ node_rank ] == nullptr )
                 aux[ node_rank ] = n;
@@ -729,6 +737,7 @@ class fibonacci_heap :
 
                     aux[ node_rank ] = nullptr;
                     node_rank        = n->child_count();
+                    BOOST_ASSERT( node_rank < max_degree );
                 } while ( aux[ node_rank ] != nullptr );
                 aux[ node_rank ] = n;
             }
diff --git a/include/boost/heap/heap_concepts.hpp b/include/boost/heap/heap_concepts.hpp
index d088074..502ee26 100644
--- a/include/boost/heap/heap_concepts.hpp
+++ b/include/boost/heap/heap_concepts.hpp
@@ -101,6 +101,6 @@ struct MutablePriorityQueue : PriorityQueue< C >
     bool equal, not_equal;
 };
 
-}}     // namespace boost::heap
+}} // namespace boost::heap
 
 #endif /* BOOST_HEAP_CONCEPTS_HPP */
diff --git a/include/boost/heap/heap_merge.hpp b/include/boost/heap/heap_merge.hpp
index 0c8c7d0..e38626d 100644
--- a/include/boost/heap/heap_merge.hpp
+++ b/include/boost/heap/heap_merge.hpp
@@ -61,7 +61,7 @@ struct heap_merge_emulate
             rhs.pop();
         }
 
-        lhs.set_stability_count( ( std::max )( lhs.get_stability_count(), rhs.get_stability_count() ) );
+        lhs.set_stability_count( (std::max)( lhs.get_stability_count(), rhs.get_stability_count() ) );
         rhs.set_stability_count( 0 );
     }
 };
@@ -118,6 +118,6 @@ void heap_merge( Heap1& lhs, Heap2& rhs )
 }
 
 
-}}     // namespace boost::heap
+}} // namespace boost::heap
 
 #endif /* BOOST_HEAP_MERGE_HPP */
diff --git a/include/boost/heap/pairing_heap.hpp b/include/boost/heap/pairing_heap.hpp
index 96319c8..e52db84 100644
--- a/include/boost/heap/pairing_heap.hpp
+++ b/include/boost/heap/pairing_heap.hpp
@@ -267,6 +267,8 @@ class pairing_heap :
     /// \copydoc boost::heap::priority_queue::operator=(priority_queue const & rhs)
     pairing_heap& operator=( pairing_heap const& rhs )
     {
+        if ( this == &rhs )
+            return *this;
         clear();
         size_holder::set_size( rhs.get_size() );
         static_cast< super_t& >( *this ) = rhs;
@@ -585,7 +587,7 @@ class pairing_heap :
         rhs.set_size( 0 );
         rhs.root = nullptr;
 
-        super_t::set_stability_count( ( std::max )( super_t::get_stability_count(), rhs.get_stability_count() ) );
+        super_t::set_stability_count( (std::max)( super_t::get_stability_count(), rhs.get_stability_count() ) );
         rhs.set_stability_count( 0 );
     }
 
diff --git a/include/boost/heap/policies.hpp b/include/boost/heap/policies.hpp
index a92edfe..5779276 100644
--- a/include/boost/heap/policies.hpp
+++ b/include/boost/heap/policies.hpp
@@ -180,6 +180,6 @@ struct arity
 {};
 #endif
 
-}}     // namespace boost::heap
+}} // namespace boost::heap
 
 #endif /* BOOST_HEAP_POLICIES_HPP */
diff --git a/include/boost/heap/priority_queue.hpp b/include/boost/heap/priority_queue.hpp
index 25be7da..b27577d 100644
--- a/include/boost/heap/priority_queue.hpp
+++ b/include/boost/heap/priority_queue.hpp
@@ -409,6 +409,6 @@ class priority_queue :
     }
 };
 
-}}     // namespace boost::heap
+}} // namespace boost::heap
 
 #endif /* BOOST_HEAP_PRIORITY_QUEUE_HPP */
diff --git a/include/boost/heap/skew_heap.hpp b/include/boost/heap/skew_heap.hpp
index 1b67834..1ca5a2d 100644
--- a/include/boost/heap/skew_heap.hpp
+++ b/include/boost/heap/skew_heap.hpp
@@ -371,6 +371,8 @@ class skew_heap :
     /// \copydoc boost::heap::priority_queue::operator=(priority_queue const & rhs)
     skew_heap& operator=( skew_heap const& rhs )
     {
+        if ( this == &rhs )
+            return *this;
         clear();
         size_holder::set_size( rhs.get_size() );
         static_cast< super_t& >( *this ) = rhs;
@@ -554,7 +556,7 @@ class skew_heap :
         rhs.root = nullptr;
         sanity_check();
 
-        super_t::set_stability_count( ( std::max )( super_t::get_stability_count(), rhs.get_stability_count() ) );
+        super_t::set_stability_count( (std::max)( super_t::get_stability_count(), rhs.get_stability_count() ) );
         rhs.set_stability_count( 0 );
     }
 
diff --git a/test/common_heap_tests.hpp b/test/common_heap_tests.hpp
index ff9ed33..f17f782 100644
--- a/test/common_heap_tests.hpp
+++ b/test/common_heap_tests.hpp
@@ -20,7 +20,7 @@
 #include <boost/container/pmr/polymorphic_allocator.hpp>
 #include <boost/shared_ptr.hpp>
 
-#include <boost/test/tools/old/interface.hpp>
+#include <boost/test/unit_test.hpp>
 #include <boost/test/unit_test_log.hpp>
 
 #include <boost/heap/heap_concepts.hpp>