4525. task's final_suspend should move the result

Section: 33.13.6.5 [task.promise] Status: New Submitter: Dietmar Kühl Opened: 2026-02-21 Last modified: 2026-02-22

Priority: Not Prioritized

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Discussion:

In 33.13.6.5 [task.promise] p6.3 the *result is passed to set_value without std::moveing: set_value(std::move(RCVR(*this)), *result). Once set_value is called the operation state object where result is stored just gets destroyed. The second argument to set_value should be std::move(*result).

Proposed resolution:

This wording is relative to N5032.

1. Change 33.13.6.5 [task.promise] p6.3 to std::move the *result:

   auto final_suspend() noexcept;
   

   -6- Returns: An awaitable object of unspecified type (7.6.2.4 [expr.await]) whose member functions arrange for the completion of the asynchronous operation associated with STATE(*this) by invoking:

   -6.1- -- set_error(std::move(RCVR(*this)), std::move(e)) if errors.index() is greater than zero and e is the value held by errors, otherwise

   -6.2- -- set_value(std::move(RCVR(*this))) if is_void<T> is true, and otherwise

   -6.3- -- set_value(std::move(RCVR(*this)), std::move(*result)).