Suggested resolution:

When a coroutine is invoked, a copy is created for each coroutine parameter. Each such copy is an object or reference with automatic storage duration that and has the same type as the corresponding parameter. Each copy is direct-initialized (9.5 [dcl.init]) from an lvalue referring to the corresponding parameter if the parameter is an lvalue reference, and from an xvalue referring to it otherwise. If the type of the copy is an rvalue reference type, then for the purpose of this initialization the value category of the corresponding parameter is an rvalue. A reference to use of a parameter in the function-body function-body of the coroutine and in the call to the coroutine promise constructor is replaced by a reference to its copy. The initialization and destruction of each parameter copy...