From e5b678a67398158240d7a64c82787c6a99ebc9eb Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Tue, 2 Jun 2015 18:07:11 +0100
Subject: [PATCH] Fix issue with ambiguous conversions.

---
 include/boost/multiprecision/traits/is_backend.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/boost/multiprecision/traits/is_backend.hpp b/include/boost/multiprecision/traits/is_backend.hpp
index bd9458c9..bb332b3e 100644
--- a/include/boost/multiprecision/traits/is_backend.hpp
+++ b/include/boost/multiprecision/traits/is_backend.hpp
@@ -50,7 +50,7 @@ namespace boost{ namespace multiprecision{  namespace detail{
    template <bool b, class T, class U>
    struct is_second_backend_imp{ static const bool value = false; };
    template <class T, class U>
-   struct is_second_backend_imp<true, T, U>{ static const bool value = is_convertible<T, number<U> >::value || is_convertible<T, number<U, et_off> >::value; };
+   struct is_second_backend_imp<true, T, U>{ static const bool value = (is_convertible<T, number<U, et_on> >::value || is_convertible<T, number<U, et_off> >::value) && !is_first_backend<T, U>::value; };
 
    template <class T, class U>
    struct is_second_backend : is_second_backend_imp<is_backend<U>::value, T, U> {};