Fix use after free and calls to operator comma in debug mode

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@232703 91177308-0d34-0410-b5e6-96231b3b80d8

include/list

@@ -1480,7 +1480,7 @@ list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,
         try
         {
 #endif  // _LIBCPP_NO_EXCEPTIONS
-            for (++__f; __f != __l; ++__f, ++__e, ++__ds)
+            for (++__f; __f != __l; ++__f, (void) ++__e, (void) ++__ds)
             {
                 __hold.reset(__node_alloc_traits::allocate(__na, 1));
                 __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);

src/debug.cpp

@@ -214,10 +214,10 @@ __libcpp_db::__erase_i(void* __i)
             else
                 q->__next_ = p->__next_;
             __c_node* c = p->__c_;
-            free(p);
             --__isz_;
             if (c != nullptr)
                 c->__remove(p);
+            free(p);
         }
     }
 }