Proposed resolution:

This wording is relative to N5014.

1. Modify [task.promise] as indicated:

   namespace std::execution {
     template<class T, class Environment>
     class task<T, Environment>::promise_type {
     public:
       […]
       void uncaughtunhandled_exception();
       coroutine_handle<> unhandled_stopped();    
       […]
     };
   }
   

   […]

   void uncaughtunhandled_exception();
   

   -12- Effects: If the signature `set_error_t(exception_ptr)` is not an element of `error_types`, calls `terminate()` ([except.terminate]). Otherwise, stores `current_exception()` into errors.

[ 2025-10-23; Reflector poll. ]

Set status to Tentatively Ready after five votes in favour during reflector poll.

According to [dcl.fct.def.coroutine], a function of name `unhandled_exception` may be called by the language mechanisms. However, std::execution::task<T, Environment>::promise_type has an `uncaught_exception function` instead, which won't be implicitly called.

In P3552R3, `unhandled_exception` was discussed, but the wording specified `uncaught_exception`, which looks like a mistake. Moreover, the paper didn't talk about the status of `uncaught_exception` in the zombie name list ([tab:zombie.names.std]). Perhaps `unhandled_exception` is the correct function name.