diff --git a/include/boost/asio/detail/bind_handler.hpp b/include/boost/asio/detail/bind_handler.hpp
index c8136a1f..6b515db9 100644
--- a/include/boost/asio/detail/bind_handler.hpp
+++ b/include/boost/asio/detail/bind_handler.hpp
@@ -37,7 +37,7 @@ public:
 
   void operator()()
   {
-    handler_(arg1_);
+    handler_(static_cast<const Arg1&>(arg1_));
   }
 
   void operator()() const
@@ -94,7 +94,8 @@ public:
 
   void operator()()
   {
-    handler_(arg1_, arg2_);
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_));
   }
 
   void operator()() const
@@ -154,7 +155,9 @@ public:
 
   void operator()()
   {
-    handler_(arg1_, arg2_, arg3_);
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_),
+        static_cast<const Arg3&>(arg3_));
   }
 
   void operator()() const
@@ -218,7 +221,10 @@ public:
 
   void operator()()
   {
-    handler_(arg1_, arg2_, arg3_, arg4_);
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_),
+        static_cast<const Arg3&>(arg3_),
+        static_cast<const Arg4&>(arg4_));
   }
 
   void operator()() const
@@ -289,7 +295,11 @@ public:
 
   void operator()()
   {
-    handler_(arg1_, arg2_, arg3_, arg4_, arg5_);
+    handler_(static_cast<const Arg1&>(arg1_),
+        static_cast<const Arg2&>(arg2_),
+        static_cast<const Arg3&>(arg3_),
+        static_cast<const Arg4&>(arg4_),
+        static_cast<const Arg5&>(arg5_));
   }
 
   void operator()() const
diff --git a/include/boost/asio/impl/read.hpp b/include/boost/asio/impl/read.hpp
index e51210ee..2100a747 100644
--- a/include/boost/asio/impl/read.hpp
+++ b/include/boost/asio/impl/read.hpp
@@ -160,7 +160,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -212,7 +212,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -317,7 +317,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
diff --git a/include/boost/asio/impl/read_at.hpp b/include/boost/asio/impl/read_at.hpp
index 0eb064b5..cc7bc808 100644
--- a/include/boost/asio/impl/read_at.hpp
+++ b/include/boost/asio/impl/read_at.hpp
@@ -173,7 +173,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -226,7 +226,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -338,7 +338,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
diff --git a/include/boost/asio/impl/write.hpp b/include/boost/asio/impl/write.hpp
index 0792f2cb..c7adc428 100644
--- a/include/boost/asio/impl/write.hpp
+++ b/include/boost/asio/impl/write.hpp
@@ -146,7 +146,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -198,7 +198,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -249,7 +249,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -328,7 +328,7 @@ namespace detail
     }
 
     void operator()(const boost::system::error_code& ec,
-        std::size_t bytes_transferred)
+        const std::size_t bytes_transferred)
     {
       streambuf_.consume(bytes_transferred);
       handler_(ec, bytes_transferred);
diff --git a/include/boost/asio/impl/write_at.hpp b/include/boost/asio/impl/write_at.hpp
index daa14420..90f9bc1b 100644
--- a/include/boost/asio/impl/write_at.hpp
+++ b/include/boost/asio/impl/write_at.hpp
@@ -157,7 +157,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -211,7 +211,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -264,7 +264,7 @@ namespace detail
             break;
         }
 
-        handler_(ec, total_transferred_);
+        handler_(ec, static_cast<const std::size_t>(total_transferred_));
       }
     }
 
@@ -347,7 +347,7 @@ namespace detail
     }
 
     void operator()(const boost::system::error_code& ec,
-        std::size_t bytes_transferred)
+        const std::size_t bytes_transferred)
     {
       streambuf_.consume(bytes_transferred);
       handler_(ec, bytes_transferred);