Fix overloads that are ambiguous when using default completion tokens

include/boost/beast/core/basic_stream.hpp

@@ -1026,6 +1026,10 @@ public:
         ,class = typename std::enable_if<
             net::is_endpoint_sequence<
                 EndpointSequence>::value>::type
+        ,class = typename std::enable_if<
+            !net::is_connect_condition<RangeConnectHandler,
+                decltype(std::declval<const EndpointSequence&>().begin())>::value
+        >::type
     #endif
     >
     BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(
@@ -1132,6 +1136,10 @@ public:
         ,class = typename std::enable_if<
             net::is_endpoint_sequence<
                 EndpointSequence>::value>::type
+        ,class = typename std::enable_if<
+            net::is_connect_condition<ConnectCondition,
+                decltype(std::declval<const EndpointSequence&>().begin())>::value
+        >::type
     #endif
     >
     BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(
@@ -1204,7 +1212,13 @@ public:
         BOOST_ASIO_COMPLETION_TOKEN_FOR(
             void(error_code, Iterator))
             IteratorConnectHandler =
-                net::default_completion_token_t<executor_type>>
+                net::default_completion_token_t<executor_type>
+    #if ! BOOST_BEAST_DOXYGEN
+        ,class = typename std::enable_if<
+            !net::is_connect_condition<IteratorConnectHandler, Iterator>::value
+        >::type
+    #endif
+    >
     BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(
         IteratorConnectHandler,
         void(error_code, Iterator))
@@ -1278,7 +1292,13 @@ public:
         BOOST_ASIO_COMPLETION_TOKEN_FOR(
             void(error_code, Iterator))
             IteratorConnectHandler =
-                net::default_completion_token_t<executor_type>>
+                net::default_completion_token_t<executor_type>
+    #if ! BOOST_BEAST_DOXYGEN
+        ,class = typename std::enable_if<
+            net::is_connect_condition<ConnectCondition, Iterator>::value
+        >::type
+    #endif
+    >
     BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(
         IteratorConnectHandler,
         void(error_code, Iterator))

include/boost/beast/core/impl/basic_stream.hpp

@@ -905,6 +905,7 @@ template<class Protocol, class Executor, class RatePolicy>
 template<
     class EndpointSequence,
     BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, typename Protocol::endpoint)) RangeConnectHandler,
+    class,
     class>
 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(RangeConnectHandler,void(error_code, typename Protocol::endpoint))
 basic_stream<Protocol, Executor, RatePolicy>::
@@ -927,6 +928,7 @@ template<
     class EndpointSequence,
     class ConnectCondition,
     BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, typename Protocol::endpoint)) RangeConnectHandler,
+    class,
     class>
 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(RangeConnectHandler,void (error_code, typename Protocol::endpoint))
 basic_stream<Protocol, Executor, RatePolicy>::
@@ -948,7 +950,8 @@ async_connect(
 template<class Protocol, class Executor, class RatePolicy>
 template<
     class Iterator,
-    BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler>
+    BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler,
+    class>
 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(IteratorConnectHandler,void (error_code, Iterator))
 basic_stream<Protocol, Executor, RatePolicy>::
 async_connect(
@@ -969,7 +972,8 @@ template<class Protocol, class Executor, class RatePolicy>
 template<
     class Iterator,
     class ConnectCondition,
-    BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler>
+    BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler,
+    class>
 BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(IteratorConnectHandler,void (error_code, Iterator))
 basic_stream<Protocol, Executor, RatePolicy>::
 async_connect(

include/boost/beast/websocket/impl/accept.hpp

@@ -603,7 +603,11 @@ template<
 BOOST_BEAST_ASYNC_RESULT1(AcceptHandler)
 stream<NextLayer, deflateSupported>::
 async_accept(
-    AcceptHandler&& handler)
+    AcceptHandler&& handler,
+    typename std::enable_if<
+        ! net::is_const_buffer_sequence<
+        AcceptHandler>::value>::type*
+)
 {
     static_assert(is_async_stream<next_layer_type>::value,
         "AsyncStream type requirements not met");
@@ -627,6 +631,9 @@ stream<NextLayer, deflateSupported>::
 async_accept(
     ConstBufferSequence const& buffers,
     AcceptHandler&& handler,
+    typename std::enable_if<
+        net::is_const_buffer_sequence<
+        ConstBufferSequence>::value>::type*,
     typename std::enable_if<
         ! http::detail::is_header<
         ConstBufferSequence>::value>::type*

include/boost/beast/websocket/stream.hpp

@@ -1381,7 +1381,13 @@ public:
     async_accept(
         AcceptHandler&& handler =
             net::default_completion_token_t<
-                executor_type>{});
+                executor_type>{}
+#ifndef BOOST_BEAST_DOXYGEN
+        , typename std::enable_if<
+            ! net::is_const_buffer_sequence<
+            AcceptHandler>::value>::type* = nullptr
+#endif
+    );
 
     /** Perform the WebSocket handshake asynchronously in the server role.
 
@@ -1454,6 +1460,9 @@ public:
             net::default_completion_token_t<
                 executor_type>{}
 #ifndef BOOST_BEAST_DOXYGEN
+        , typename std::enable_if<
+            net::is_const_buffer_sequence<
+            ConstBufferSequence>::value>::type* = 0
         , typename std::enable_if<
             ! http::detail::is_header<
             ConstBufferSequence>::value>::type* = 0