NVIDIA / NVIDIA/stdexec

`just` senders are move/copy constructible but not assignable

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C++
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Description

See https://godbolt.org/z/GW7cfea31 for a reproducer. I would expect them to be assignable if they're copy/move constructible. The source seems to be __make_tuple (https://github.com/NVIDIA/stdexec/blob/869fb2a7767d30bff486b589533b0346e4dd5454/include/stdexec/__detail/__basic_sender.hpp#L612-L653) which is a lambda with captures, which makes the just sender non-assignable. Is this expected or intentional? Does __make_tuple need to be implemented that way?

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Research direction

Start with the Godbolt reproducer, then inspect __make_tuple in include/stdexec/__detail/__basic_sender.hpp at lines 612-653. Determine whether the observed non-assignability of just senders is intentional or should change, and document or validate the expected behavior with a focused test.

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Assessment

Tech stack
cpp
Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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