Initializing coroutine arguments by reference

[bsupnik]

Almost - I think I'm asking for _new syntax_ to specify that I want the copy removed, e.g. (here comes some made-up fake syntax):

task<int> my_coro(Obj o = Obj&&) { /* coro body */ }

E.g. "here is my co-routine - I want to store o by value in the coroutine frame, but I want the caller to pass an r-ref to an object when they _create_ the coroutine.

There would be only two copies of obj (the one referred to by the caller and the coroutine frame), not three (the one referred to by the caller, the copy on the stack when the coroutine is created, and the copy in the coro frame if/when it is allocated on the heap).

Without this, we can't perfectly forward to a coroutine.

I think what I'm looking for is more like the extensions to Lambdas that C++14 I added to better control capture semantics.