Deduction guides for std::chrono::zoned_time 

zoned_time() -> zoned_time<std::chrono::seconds>;
 (1) (since C++20) 
template< class Duration >
zoned_time(std::chrono::sys_time<Duration>) 
    -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>>;
 (2) (since C++20) 
template< class TimeZonePtrOrName >
zoned_time(TimeZonePtrOrName) -> zoned_time<std::chrono::seconds, /* see below */>;
 (3) (since C++20) 
template< class TimeZonePtrOrName, class Duration >
zoned_time(TimeZonePtrOrName, std::chrono::sys_time<Duration>)
    -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;
 (4) (since C++20) 
template< class TimeZonePtrOrName, class Duration >
zoned_time(TimeZonePtrOrName, std::chrono::local_time<Duration>,
           std::chrono::choose = std::chrono::choose::earliest)
    -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;
 (5) (since C++20) 
template< class TimeZonePtrOrName, class Duration, class TimeZonePtr2 >
zoned_time(TimeZonePtrOrName, std::chrono::zoned_time<Duration, TimeZonePtr2>,
           std::chrono::choose = std::chrono::choose::earliest)
    -> zoned_time<std::common_type_t<Duration, std::chrono::seconds>, /* see below */>;
 (6) (since C++20)

Six deduction guides are provided for zoned_time. They normalize Duration to a minimum resolution of std::chrono::seconds, and provide correct handling for time zone names specified using types convertible to std::string_view.

3-6) If std::is_convertible_v<TimeZonePtrOrName, std::string_view> is true, the deduced second template argument is const std::chrono::time_zone*. Otherwise it is TimeZonePtrOrName.

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