std::variant::~variant(3)

NAME
std::variant::~variant - std::variant::~variant

Synopsis
   ~variant(); (since C++17)
                        (until C++20)
   constexpr ~variant(); (since C++20)
   If valueless_by_exception() is true, does nothing. Otherwise, destroys the currently
   contained value.
   This destructor is trivial if std::is_trivially_destructible_v<T_i> is true for all
   T_i in Types....

Example
// Run this code
 #include <variant>
 #include <cstdio>
 int main()
 {
     struct X { ~X() { puts("X::~X();"); } };
     struct Y { ~Y() { puts("Y::~Y();"); } };
     {
         puts("entering block #1");
         std::variant<X,Y> var;
         puts("leaving block #1");
     }
     {
         puts("entering block #2");
         std::variant<X,Y> var{ std::in_place_index_t<1>{} }; // constructs var(Y)
         puts("leaving block #2");
     }
 }

Output:
 entering block #1
 leaving block #1
 X::~X();
 entering block #2
 leaving block #2
 Y::~Y();
   Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
     DR Applied to Behavior as published Correct behavior
                      the destructor was not constexpr while
   P2231R1 C++20 non-trivial destructors can be constexpr in made constexpr
                      C++20