From f3998fb2bbbcd29aacfc1b27d92af570d154fb9b Mon Sep 17 00:00:00 2001
From: Nikita Kniazev <nok.raven@gmail.com>
Date: Tue, 26 Jan 2021 23:16:25 +0300
Subject: [PATCH] Missing inline keyword. Fixes #638

---
 include/boost/spirit/home/support/utree/operators.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/boost/spirit/home/support/utree/operators.hpp b/include/boost/spirit/home/support/utree/operators.hpp
index a0aaa029d..fdefe3901 100644
--- a/include/boost/spirit/home/support/utree/operators.hpp
+++ b/include/boost/spirit/home/support/utree/operators.hpp
@@ -540,7 +540,7 @@ namespace boost { namespace spirit
     BOOST_SPIRIT_UTREE_CREATE_INTEGRAL_FUNCTION(UNARY,  invert,      ~a)
 
     // avoid `'~' on an expression of type bool` warning
-    template <> utree function_impl_invert::eval<bool>(bool const& a)
+    template <> inline utree function_impl_invert::eval<bool>(bool const& a)
     {
         return utree(!a);
     }