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diff --git a/third-party/boost-math/include/boost/math/ccmath/isless.hpp b/third-party/boost-math/include/boost/math/ccmath/isless.hpp
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+++ b/third-party/boost-math/include/boost/math/ccmath/isless.hpp
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+//  (C) Copyright Matt Borland 2022.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MATH_CCMATH_ISLESS_HPP
+#define BOOST_MATH_CCMATH_ISLESS_HPP
+
+#include <boost/math/ccmath/detail/config.hpp>
+
+#ifdef BOOST_MATH_NO_CCMATH
+#error "The header <boost/math/isless.hpp> can only be used in C++17 and later."
+#endif
+
+#include <boost/math/ccmath/isnan.hpp>
+
+namespace boost::math::ccmath {
+
+template <typename T1, typename T2 = T1>
+inline constexpr bool isless(T1 x, T2 y) noexcept
+{
+    if (BOOST_MATH_IS_CONSTANT_EVALUATED(x))
+    {
+        if (boost::math::ccmath::isnan(x) || boost::math::ccmath::isnan(y))
+        {
+            return false;
+        }
+        else
+        {
+            return x < y;
+        }
+    }
+    else
+    {
+        using std::isless;
+        return isless(x, y);
+    }
+}
+
+} // Namespaces
+
+#endif // BOOST_MATH_CCMATH_ISLESS_HPP