From b059a98b27b40cd284e08a54493c25363d743557 Mon Sep 17 00:00:00 2001
From: Paul Dreik <github@pauldreik.se>
Date: Sun, 5 May 2019 16:21:25 +0200
Subject: [PATCH] trigger undefined behaviour with NaN durations

---
 test/chrono-test.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/test/chrono-test.cc b/test/chrono-test.cc
index 573606d8dbdf..71a64d462102 100644
--- a/test/chrono-test.cc
+++ b/test/chrono-test.cc
@@ -314,4 +314,14 @@ TEST(ChronoTest, NegativeDuration) {
   EXPECT_EQ("-00:01", fmt::format("{:%M:%S}", std::chrono::duration<double>(-1)));
 }
 
+TEST(ChronoTest, DurationIsFloatNaN) {
+  const std::chrono::duration<float> d{std::nanf("1")};
+  auto ignored=fmt::format("{:%I}",d);
+}
+
+TEST(ChronoTest, DurationIsDoubleNaN) {
+  const std::chrono::duration<double> d{std::nan("1")};
+  auto ignored=fmt::format("{:%I}",d);
+}
+
 #endif  // FMT_STATIC_THOUSANDS_SEPARATOR