Fix copy_time_to: Copy nsec instead of usec

`copy_time_to` is a helper function for date and time calculations.
It's being used by `prev_week`, `next_week` and `prev_weekday` to keep
the time fraction when jumping around between days.

Previously the nanoseconds part was lost during the operation. This
lead to problems in practice if you were using the `end_of_day`
calculation. Resulting in the time fraction of `end_of_day` not being
the same as next week's `end_of_day`.

With this fix `copy_time_to` doesn't forget the `nsec` digits.

1 files changed, 1 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
index c614f14289..f2ba7fdda5 100644
--- a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
@@ -334,7 +334,7 @@ module DateAndTime
       end
 
       def copy_time_to(other)
-        other.change(hour: hour, min: min, sec: sec, usec: try(:usec))
+        other.change(hour: hour, min: min, sec: sec, nsec: try(:nsec))
       end
   end
 end