Inconsistent behavior of `just` and `then`

[mpusz]

I thought that just(42) should be equivalent to stdexec::just() | stdexec::then([]{ return 42; }) but it seems they are not. The code below behaves differently for each of those. Why?

auto use = [](auto task) {
  auto work = stdexec::when_all(std::move(task), stdexec::just_error(-1));
  auto [res] = stdexec::sync_wait(std::move(work) | stdexec::upon_error([](int e){ return e; })).value();
  std::cout << "res: " << res << '\n';
};

use(stdexec::just(42)); // compiles fine
use(stdexec::just() | stdexec::then([]{ return 42; })); // ERROR :-(

[mpusz]

I realize that just_error usage here might be controversial, but it does not excuse the differences between task variations.

[LeeHowes]

What's the difference you are seeing? You have a double move of task instead of using work in the second line. Is just's result copying for move and then's is destructively moving?

[mpusz]

@LeeHowes , sorry. Copy-paste error. Fixed.