From cacd3ae543b1718d9fa8004b8a23a9dc13e6189c Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Sun, 6 Sep 2020 15:35:52 +0200
Subject: [PATCH] Non-zero denominator contract added for ratio

---
 src/include/units/ratio.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/include/units/ratio.h b/src/include/units/ratio.h
index 2a483a46..c21f196c 100644
--- a/src/include/units/ratio.h
+++ b/src/include/units/ratio.h
@@ -29,6 +29,7 @@
 #include <type_traits>
 #include <tuple>
 #include <algorithm>
+#include <gsl/gsl_assert>
 
 namespace units {
 
@@ -50,6 +51,7 @@ struct ratio {
 
   explicit constexpr ratio(std::intmax_t n, std::intmax_t d = 1, std::intmax_t e = 0): num(n), den(d), exp(e)
   {
+    Expects(den != 0);
     detail::normalize(num, den, exp);
   }