std::experimental::erased_type
From cppreference.com
< cpp | experimental
The class erased_type is an empty struct that serves as a placeholder for a type in situations where the actual type is determined at runtime. For example, in classes that use type-erased allocators, the nested typedef allocator_type is an alias for erased_type.
Notes
erased_type is removed in LFTS v3 because std::pmr::polymorphic_allocator<> is preferable for type erasure.
