From 34cea300e5711482f9651f2aad5d997670bc52e9 Mon Sep 17 00:00:00 2001
From: Neil Groves <neil@grovescomputing.com>
Date: Mon, 16 Sep 2013 23:23:38 +0000
Subject: [PATCH] [boost][range] - fix a very odd compilation problem in
 range_size that only occurs on clang 4.2 on the Mac (clang 4.2 on linux is
 fine)

[SVN r85717]
---
 include/boost/range/size_type.hpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/boost/range/size_type.hpp b/include/boost/range/size_type.hpp
index dab2f0d..cc99ef3 100644
--- a/include/boost/range/size_type.hpp
+++ b/include/boost/range/size_type.hpp
@@ -76,14 +76,22 @@ namespace boost
     struct range_size :
         detail::range_size<T>
     {
+// Very strange things happen on some compilers that have the range concept
+// asserts disabled. This preprocessor condition is clearly redundant on a
+// working compiler but is vital for at least some compilers such as clang 4.2
+// but only on the Mac!
+#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT == 1
         BOOST_RANGE_CONCEPT_ASSERT((boost::SinglePassRangeConcept<T>));
+#endif
     };
 
     template< class T >
     struct range_size<const T >
         : detail::range_size<T>
     {
+#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT == 1        
         BOOST_RANGE_CONCEPT_ASSERT((boost::SinglePassRangeConcept<T>));
+#endif
     };
 
 } // namespace boost