diagnostics refinements

Author: zajo

include/boost/leaf/detail/demangle.hpp

@@ -23,8 +23,6 @@
 #   include <string>
 #endif
 
-#if BOOST_LEAF_CFG_DIAGNOSTICS
-
 // __has_include is currently supported by GCC and Clang. However GCC 4.9 may have issues and
 // returns 1 for 'defined( __has_include )', while '__has_include' is actually not supported:
 // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63662
@@ -46,8 +44,6 @@
 #   endif
 #endif
 
-#endif // #if BOOST_LEAF_CFG_DIAGNOSTICS
-
 namespace boost { namespace leaf {
 
 namespace detail

include/boost/leaf/detail/diagnostics_writer.hpp

@@ -8,10 +8,22 @@
 #include <boost/leaf/writer.hpp>
 #include <boost/leaf/detail/exception_base.hpp>
 
-#include <iosfwd>
+#include <boost/leaf/config.hpp>
+#include <type_traits>
+
+#if BOOST_LEAF_CFG_DIAGNOSTICS
+#   include <iostream>
+#else
+#   include <iosfwd>
+#endif
 
 namespace boost { namespace leaf {
 
+template <class E>
+struct show_in_diagnostics: std::integral_constant<bool, BOOST_LEAF_CFG_DIAGNOSTICS>
+{
+};
+
 namespace detail
 {
     template <class T, class E = void>

include/boost/leaf/error.hpp

@@ -9,11 +9,7 @@
 #include <boost/leaf/detail/optional.hpp>
 #include <boost/leaf/detail/function_traits.hpp>
 #include <boost/leaf/detail/capture_list.hpp>
-
-#if BOOST_LEAF_CFG_DIAGNOSTICS
-#   include <boost/leaf/detail/diagnostics_writer.hpp>
-#   include <ostream>
-#endif
+#include <boost/leaf/detail/diagnostics_writer.hpp>
 
 #include <cstring>
 
@@ -104,10 +100,8 @@ namespace detail
     void serialize_(Writer & w, E const & e)
     {
         serialize(w, e);
-    #if BOOST_LEAF_CFG_DIAGNOSTICS
         if( detail::diagnostics_writer * ow = w.template get<detail::diagnostics_writer>() )
             ow->write(e);
-    #endif
     }
 }
 

include/boost/leaf/writer.hpp

@@ -21,11 +21,6 @@
 
 namespace boost { namespace leaf {
 
-template <class E>
-struct show_in_diagnostics: std::true_type
-{
-};
-
 class writer
 {
     parsed const type_;