From bcd0d91dc79dcaf71d28a23e499c0135fb4b769b Mon Sep 17 00:00:00 2001
From: Romain Geissler <romain.geissler@amadeus.com>
Date: Thu, 5 Dec 2019 21:54:45 +0000
Subject: [PATCH] Ignore unused argument warning when compiling with -DNDEBUG.

The argument "state" is indeed used only in the BOOST_ASSERT.
---
 include/boost/msm/back/state_machine.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/boost/msm/back/state_machine.hpp b/include/boost/msm/back/state_machine.hpp
index 640802d..1623207 100644
--- a/include/boost/msm/back/state_machine.hpp
+++ b/include/boost/msm/back/state_machine.hpp
@@ -19,6 +19,7 @@
 
 #include <boost/core/no_exceptions_support.hpp>
 
+#include <boost/core/ignore_unused.hpp>
 #include <boost/mpl/contains.hpp>
 #include <boost/mpl/deref.hpp>
 #include <boost/mpl/assert.hpp>
@@ -442,6 +443,7 @@ private:
 
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
             BOOST_STATIC_CONSTANT(int, next_state = (get_state_id<stt,next_state_type>::type::value));
+            boost::ignore_unused(state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
             // if T1 is an exit pseudo state, then take the transition only if the pseudo exit state is active
             if (has_pseudo_exit<T1>::type::value &&
@@ -521,6 +523,7 @@ private:
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
             BOOST_STATIC_CONSTANT(int, next_state = (get_state_id<stt,next_state_type>::type::value));
+            boost::ignore_unused(state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
             // if T1 is an exit pseudo state, then take the transition only if the pseudo exit state is active
             if (has_pseudo_exit<T1>::type::value &&
@@ -584,6 +587,7 @@ private:
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
             BOOST_STATIC_CONSTANT(int, next_state = (get_state_id<stt,next_state_type>::type::value));
+            boost::ignore_unused(state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
 
             // if T1 is an exit pseudo state, then take the transition only if the pseudo exit state is active
@@ -650,6 +654,7 @@ private:
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
             BOOST_STATIC_CONSTANT(int, next_state = (get_state_id<stt,next_state_type>::type::value));
+            boost::ignore_unused(state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
 
             // if T1 is an exit pseudo state, then take the transition only if the pseudo exit state is active
@@ -701,6 +706,7 @@ private:
         {
 
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
+            boost::ignore_unused(state, current_state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
             if (!check_guard(fsm,evt))
             {
@@ -743,6 +749,7 @@ private:
         static HandledEnum execute(library_sm& fsm, int , int state, transition_event const& evt)
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
+            boost::ignore_unused(state, current_state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
             if (!check_guard(fsm,evt))
             {
@@ -770,6 +777,7 @@ private:
         static HandledEnum execute(library_sm& fsm, int , int state, transition_event const& evt)
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
+            boost::ignore_unused(state, current_state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
 
             // call the action method
@@ -797,6 +805,7 @@ private:
         static HandledEnum execute(library_sm& , int , int state, transition_event const& )
         {
             BOOST_STATIC_CONSTANT(int, current_state = (get_state_id<stt,current_state_type>::type::value));
+            boost::ignore_unused(state, current_state); // Avoid warnings if BOOST_ASSERT expands to nothing.
             BOOST_ASSERT(state == (current_state));
             return HANDLED_TRUE;
         }