role_type is in boost/beast/core/role.hpp (API Change):

This enumeration is now part of the library core and
not specific to websocket.

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

@@ -972,7 +972,7 @@ template<
     class Protocol, class Executor, class RatePolicy>
 void
 teardown(
-    websocket::role_type role,
+    role_type role,
     basic_stream<Protocol, Executor, RatePolicy>& stream,
     error_code& ec)
 {
@@ -985,7 +985,7 @@ template<
     class TeardownHandler>
 void
 async_teardown(
-    websocket::role_type role,
+    role_type role,
     basic_stream<Protocol, Executor, RatePolicy>& stream,
     TeardownHandler&& handler)
 {

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

@@ -255,7 +255,7 @@ async_write_some(
 template<class NextLayer>
 void
 teardown(
-    boost::beast::websocket::role_type role,
+    boost::beast::role_type role,
     flat_stream<NextLayer>& s,
     error_code& ec)
 {
@@ -266,7 +266,7 @@ teardown(
 template<class NextLayer, class TeardownHandler>
 void
 async_teardown(
-    boost::beast::websocket::role_type role,
+    boost::beast::role_type role,
     flat_stream<NextLayer>& s,
     TeardownHandler&& handler)
 {