suppressed more null-dereference warnings

include/boost/multi_index/detail/assume.hpp

@@ -0,0 +1,44 @@
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * See http://www.boost.org/libs/multi_index for library home page.
+ */
+
+#ifndef BOOST_MULTI_INDEX_DETAIL_ASSUME_HPP
+#define BOOST_MULTI_INDEX_DETAIL_ASSUME_HPP
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
+#include <boost/assert.hpp>
+
+#ifdef __has_builtin
+#define BOOST_MULTI_INDEX_HAS_BUILTIN(x) __has_builtin(x)
+#else
+#define BOOST_MULTI_INDEX_HAS_BUILTIN(x) 0
+#endif
+
+#if !defined(NDEBUG)
+#define BOOST_MULTI_INDEX_ASSUME(cond) BOOST_ASSERT(cond)
+#elif BOOST_MULTI_INDEX_HAS_BUILTIN(__builtin_assume)
+#define BOOST_MULTI_INDEX_ASSUME(cond) __builtin_assume(cond)
+#elif defined(__GNUC__) || \
+      BOOST_MULTI_INDEX_HAS_BUILTIN(__builtin_unreachable)
+#define BOOST_MULTI_INDEX_ASSUME(cond)  \
+  do{                                   \
+    if(!(cond))__builtin_unreachable(); \
+  }while(0)
+#elif defined(_MSC_VER)
+#define BOOST_MULTI_INDEX_ASSUME(cond) __assume(cond)
+#else
+#define BOOST_MULTI_INDEX_ASSUME(cond) \
+  do{                                  \
+    static_cast<void>(false&&(cond));  \
+  }while(0)
+#endif
+
+#endif

include/boost/multi_index/detail/hash_index_node.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2003-2025 Joaquin M Lopez Munoz.
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -15,6 +15,7 @@
 
 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
 #include <boost/core/allocator_access.hpp>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/raw_ptr.hpp>
 #include <utility>
 
@@ -263,6 +264,7 @@ struct hashed_index_node_alg<Node,hashed_unique_tag>
       x->prior()=buc->prior()->prior();
       x->next()=base_pointer_from(buc->prior());
       buc->prior()=x;
+      BOOST_MULTI_INDEX_ASSUME(x->next()!=base_pointer(0));
       x->next()->prior()=x;
     }
   }
@@ -404,12 +406,14 @@ struct hashed_index_node_alg<Node,hashed_non_unique_tag>
       x->prior()=buc->prior()->prior();
       x->next()=base_pointer_from(buc->prior());
       buc->prior()=x;
+      BOOST_MULTI_INDEX_ASSUME(pointer_from(x->next())!=pointer(0));
       x->next()->prior()=x;
     }
   }
 
   static void link(pointer x,pointer first,pointer last)
   {
+    BOOST_MULTI_INDEX_ASSUME(x!=pointer(0)&&first!=pointer(0));
     x->prior()=first->prior();
     x->next()=base_pointer_from(first);
     if(is_first_of_bucket(first)){
@@ -429,6 +433,7 @@ struct hashed_index_node_alg<Node,hashed_non_unique_tag>
     else{
       pointer second=pointer_from(first->next()),
               lastbutone=last->prior();
+      BOOST_MULTI_INDEX_ASSUME(second!=pointer(0));
       second->prior()=first;
       first->prior()=last;
       lastbutone->next()=base_pointer_from(x);
@@ -655,8 +660,9 @@ private:
   static void unlink_last_but_one_of_group(pointer x,Assigner& assign)
   {
     pointer first=pointer_from(x->next()),
-            second=pointer_from(first->next()),
-            last=second->prior();
+            second=pointer_from(first->next());
+    BOOST_MULTI_INDEX_ASSUME(second!=pointer(0));
+    pointer last=second->prior();
     if(second==x){
       assign(last->prior(),first);
       assign(first->next(),base_pointer_from(last));

include/boost/multi_index/detail/ord_index_impl.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2003-2025 Joaquin M Lopez Munoz.
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -49,6 +49,7 @@
 #include <boost/core/ref.hpp>
 #include <boost/mp11/utility.hpp>
 #include <boost/multi_index/detail/adl_swap.hpp>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/bidir_node_iterator.hpp>
 #include <boost/multi_index/detail/do_not_copy_elements_tag.hpp>
 #include <boost/multi_index/detail/index_node_base.hpp>
@@ -1164,6 +1165,7 @@ private:
       else index_node_type::decrement(yy);
     }
 
+    BOOST_MULTI_INDEX_ASSUME(yy!=0);
     if(comp_(key(yy->value()),k)){
       inf.side=c?to_left:to_right;
       inf.pos=y->impl();
@@ -1218,6 +1220,7 @@ private:
       else return link_point(k,inf,ordered_unique_tag());
     } 
     else if(position==header()){ 
+      BOOST_MULTI_INDEX_ASSUME(rightmost()!=0);
       if(comp_(key(rightmost()->value()),k)){
         inf.side=to_right;
         inf.pos=rightmost()->impl();
@@ -1257,6 +1260,7 @@ private:
       else return lower_link_point(k,inf,ordered_non_unique_tag());
     } 
     else if(position==header()){
+      BOOST_MULTI_INDEX_ASSUME(rightmost()!=0);
       if(!comp_(k,key(rightmost()->value()))){
         inf.side=to_right;
         inf.pos=rightmost()->impl();

include/boost/multi_index/detail/ord_index_node.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2003-2025 Joaquin M Lopez Munoz.
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -43,6 +43,7 @@
 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
 #include <boost/core/allocator_access.hpp>
 #include <cstddef>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/raw_ptr.hpp>
 
 #if !defined(BOOST_MULTI_INDEX_DISABLE_COMPRESSED_ORDERED_INDEX_NODES)
@@ -269,6 +270,7 @@ public:
     }
     else{
       pointer y=x->parent();
+      BOOST_MULTI_INDEX_ASSUME(y!=pointer(0));
       while(x==y->right()){
         x=y;
         y=y->parent();
@@ -279,6 +281,7 @@ public:
 
   static void decrement(pointer& x)
   {
+    BOOST_MULTI_INDEX_ASSUME(x->color()!=red||x->parent()!=pointer(0));
     if(x->color()==red&&x->parent()->parent()==x){
       x=x->right();
     }

include/boost/multi_index/detail/rnd_index_ptr_array.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2003-2025 Joaquin M Lopez Munoz.
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -17,6 +17,7 @@
 #include <boost/core/allocator_access.hpp>
 #include <algorithm>
 #include <boost/core/noncopyable.hpp>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/auto_space.hpp>
 #include <boost/multi_index/detail/rnd_index_node.hpp>
 
@@ -87,6 +88,7 @@ public:
     *(end()+1)=*end();
     (*(end()+1))->up()=end()+1;
     *end()=x;
+    BOOST_MULTI_INDEX_ASSUME(*end()!=value_type(0));
     (*end())->up()=end();
     ++size_;
   }

include/boost/multi_index/hashed_index.hpp

@@ -22,6 +22,7 @@
 #include <boost/limits.hpp>
 #include <boost/mp11/utility.hpp>
 #include <boost/multi_index/detail/adl_swap.hpp>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/auto_space.hpp>
 #include <boost/multi_index/detail/bucket_array.hpp>
 #include <boost/multi_index/detail/do_not_copy_elements_tag.hpp>
@@ -1458,6 +1459,7 @@ private:
           node_impl_pointer x=end_->prior();
 
           /* only this can possibly throw */
+          BOOST_MULTI_INDEX_ASSUME(index_node_type::from_impl(x)!=0);
           std::size_t h=hash_(key(index_node_type::from_impl(x)->value()));
 
           hashes.data()[i]=h;
@@ -1511,6 +1513,7 @@ private:
           if(x==end_)break;
 
           /* only this can possibly throw */
+          BOOST_MULTI_INDEX_ASSUME(index_node_type::from_impl(x)!=0);
           std::size_t h=hash_(key(index_node_type::from_impl(x)->value()));
 
           hashes.data()[i]=h;

include/boost/multi_index/random_access_index.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2003-2025 Joaquin M Lopez Munoz.
+/* Copyright 2003-2026 Joaquin M Lopez Munoz.
  * Distributed under the Boost Software License, Version 1.0.
  * (See accompanying file LICENSE_1_0.txt or copy at
  * http://www.boost.org/LICENSE_1_0.txt)
@@ -21,6 +21,7 @@
 #include <boost/core/allocator_access.hpp>
 #include <boost/core/no_exceptions_support.hpp>
 #include <boost/mp11/function.hpp>
+#include <boost/multi_index/detail/assume.hpp>
 #include <boost/multi_index/detail/do_not_copy_elements_tag.hpp>
 #include <boost/multi_index/detail/index_node_base.hpp>
 #include <boost/multi_index/detail/node_handle.hpp>
@@ -1117,6 +1118,7 @@ private:
 
     for(Iterator it=first;it!=last;++it,++pp){
       *pp=static_cast<index_node_type*>(it.get_node());
+      BOOST_MULTI_INDEX_ASSUME(pp!=0);
       (*pp)->up()=pp;
     }
   }

test/Jamfile.v2

@@ -1,6 +1,6 @@
 # Boost.MultiIndex tests Jamfile
 #
-# Copyright 2003-2025 Joaquín M López Muñoz.
+# Copyright 2003-2026 Joaquín M López Muñoz.
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 # http://www.boost.org/LICENSE_1_0.txt)
@@ -37,6 +37,7 @@ project
       <toolset>msvc:<define>_CRT_SECURE_NO_WARNINGS
       <toolset>msvc:<define>_SILENCE_ALL_CXX17_DEPRECATION_WARNINGS
       <toolset>msvc:<cxxflags>/wd4494
+      <toolset>gcc:<cxxflags>-Werror=null-dereference
     ;
 
 obj boost_multi_index_key_supported : check_bmi_key_supported.cpp  ;