From 096bad2622e009fd4a5bc87890a9139ab6df6825 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <howard.hinnant@gmail.com>
Date: Thu, 13 Apr 2017 12:45:28 -0400
Subject: [PATCH] Parse should fail if fmt string is not consumed.

---
 date.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/date.h b/date.h
index 54b9668..2f6a4ea 100644
--- a/date.h
+++ b/date.h
@@ -6177,6 +6177,8 @@ from_stream(std::basic_istream<CharT, Traits>& is, const CharT* fmt,
             else
                 read(is, CharT{'%'}, width, modified);
         }
+        if (is.rdstate() != ios::goodbit && *fmt != CharT{} && !is.fail())
+            is.setstate(ios::failbit);
         if (!is.fail())
         {
             if (y != not_a_2digit_year)