NVIDIA / NVIDIA/stdexec

`nvexec::let_value` and friends don't appear to be persisting the function args

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bug cuda P1
Dominant language
C++
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Description

https://github.com/NVIDIA/stdexec/blob/1d79ecffbc5c80ad9e4a575a3294d84423bda37e/include/nvexec/stream/let_xxx.cuh#LL117-L118

The arguments to let_value's callable should be persisted for the duration of the successor operation. Here, it looks like the arguments are discarded after the callable returns the successor sender.

@senior-zero is there a reason why keeping the arguments around like stdexec::let_value does would be problematic for the CUDA stream scheduler?

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Research direction

Start at include/nvexec/stream/let_xxx.cuh around lines 117-118 and compare the lifetime handling with stdexec::let_value. Trace the successor operation to confirm whether the callable's arguments are discarded too early; done means the arguments remain available for the successor operation without breaking the CUDA stream scheduler.

Written by the indexing model from the issue text.

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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