Denis questions

• C++: What is the evaluation order of the user-defined comma operator?
• Why does a constructor which takes iterators require elements to be EmplaceConstructible?
• Type of reference binding from std::tuple [duplicate]
• Why is the address of a constexpr local variable not a constant expression?
• std::variant and ambiguous initialization
• User-defined and standard conversions
• Memory ordering with multiple releases and a single acquire
• Is implementation of double checked singleton thread-safe?
• std::unordered_set::erase complexity
• typename keyword and nested name specifier

Denis answers