Apparently temporary materialization also occurs when “when a prvalue appears as a discarded-value expression.” https://en.cppreference.com/w/cpp/language/impli

Apparently temporary materialization also occurs when “when a prvalue appears as a discarded-value expression.” https://en.cppreference.com/w/cpp/language/implicit_conversion#Temporary_materialization https://en.cppreference.com/w/cpp/language/implicit_conversi... So yes, storage for the (to-be discarded) object must be allocated, and the object is constructed into that storage. I don’t know enough about the ABI to comment about the last point.