From 5104a4afcb26dc551c92071508d9d0753f81e174 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <howard.hinnant@gmail.com>
Date: Sat, 8 Aug 2015 12:45:55 -0400
Subject: [PATCH] Revert: Make months and years not convertible to seconds: *
 After much consideration I consider this not a good change. * It introduced a
 completely arbitrary mathematical relationship   among the units. * This
 commit restores a precise relationship among the units which   is based on
 the Gregorian calendar. * However this experiment has been preserved in the
 git history.

---
 date.h                            |  3 +--
 test/date_test/durations.pass.cpp | 24 ++++++++++--------------
 2 files changed, 11 insertions(+), 16 deletions(-)

diff --git a/date.h b/date.h
index 49041d1..f7bd09e 100644
--- a/date.h
+++ b/date.h
@@ -45,8 +45,7 @@ using weeks = std::chrono::duration
     <int, std::ratio_multiply<std::ratio<7>, days::period>>;
 
 using years = std::chrono::duration
-    <int, std::ratio_subtract<std::ratio_multiply<std::ratio<146097, 400>, days::period>,
-                              std::ratio<1, 7>>>;
+    <int, std::ratio_multiply<std::ratio<146097, 400>, days::period>>;
 
 using months = std::chrono::duration
     <int, std::ratio_divide<years::period, std::ratio<12>>>;
diff --git a/test/date_test/durations.pass.cpp b/test/date_test/durations.pass.cpp
index 9be8f91..e20cf5c 100644
--- a/test/date_test/durations.pass.cpp
+++ b/test/date_test/durations.pass.cpp
@@ -42,9 +42,7 @@ static_assert( std::is_convertible<date::weeks, date::days>{}, "");
 static_assert(!std::is_convertible<date::weeks, date::months>{}, "");
 static_assert(!std::is_convertible<date::weeks, date::years>{}, "");
 
-static_assert(
-    std::chrono::seconds{2629745} < date::months{1} &&
-                                    date::months{1} < std::chrono::seconds{2629746}, "");
+static_assert(date::months{1} == std::chrono::seconds{2629746}, "");
 static_assert(date::days{30} < date::months{1} && date::months{1} < date::days{31}, "");
 static_assert(date::weeks{4} < date::months{1} && date::months{1} < date::weeks{5}, "");
 static_assert(!std::is_convertible<date::months, date::years>{}, "");
@@ -52,14 +50,12 @@ static_assert(!std::is_convertible<date::months, date::weeks>{}, "");
 static_assert(!std::is_convertible<date::months, date::days>{}, "");
 static_assert(!std::is_convertible<date::months, std::chrono::hours>{}, "");
 static_assert(!std::is_convertible<date::months, std::chrono::minutes>{}, "");
-static_assert(!std::is_convertible<date::months, std::chrono::seconds>{}, "");
-static_assert(!std::is_convertible<date::months, std::chrono::milliseconds>{}, "");
-static_assert(!std::is_convertible<date::months, std::chrono::microseconds>{}, "");
-static_assert(!std::is_convertible<date::months, std::chrono::nanoseconds>{}, "");
+static_assert( std::is_convertible<date::months, std::chrono::seconds>{}, "");
+static_assert( std::is_convertible<date::months, std::chrono::milliseconds>{}, "");
+static_assert( std::is_convertible<date::months, std::chrono::microseconds>{}, "");
+static_assert( std::is_convertible<date::months, std::chrono::nanoseconds>{}, "");
 
-static_assert(
-    std::chrono::seconds{31556951} < date::years{1} &&
-                                     date::years{1} < std::chrono::seconds{31556952}, "");
+static_assert(date::years{1} == std::chrono::seconds{31556952}, "");
 static_assert(date::days{365} < date::years{1} && date::years{1} < date::days{366}, "");
 static_assert(date::weeks{52} < date::years{1} && date::years{1} < date::weeks{53}, "");
 static_assert(date::years{1} == date::months{12}, "");
@@ -68,10 +64,10 @@ static_assert(!std::is_convertible<date::years, date::weeks>{}, "");
 static_assert(!std::is_convertible<date::years, date::days>{}, "");
 static_assert(!std::is_convertible<date::years, std::chrono::hours>{}, "");
 static_assert(!std::is_convertible<date::years, std::chrono::minutes>{}, "");
-static_assert(!std::is_convertible<date::years, std::chrono::seconds>{}, "");
-static_assert(!std::is_convertible<date::years, std::chrono::milliseconds>{}, "");
-static_assert(!std::is_convertible<date::years, std::chrono::microseconds>{}, "");
-static_assert(!std::is_convertible<date::years, std::chrono::nanoseconds>{}, "");
+static_assert( std::is_convertible<date::years, std::chrono::seconds>{}, "");
+static_assert( std::is_convertible<date::years, std::chrono::milliseconds>{}, "");
+static_assert( std::is_convertible<date::years, std::chrono::microseconds>{}, "");
+static_assert( std::is_convertible<date::years, std::chrono::nanoseconds>{}, "");
 
 static_assert(std::is_same<date::day_point::duration, date::days>{}, "");