GCC 13.2 compiler cannot resolve overloaded spawn in boost 1.86

[Wedge009]

Not sure if this is an issue with boost - downstream issue is wesnoth/wesnoth#9284

Wesnoth compiles cleanly with boost 1.85. With boost 1.86, gcc gives the following error (for example) on calls of spawn:

error: call of overloaded ‘spawn(boost::asio::io_service&, wesnothd::server::handle_new_client(socket_ptr)::<lambda(boost::asio::yield_context)>)’ is ambiguous

Only by explicitly setting a completion token can Wesnoth compile with boost 1.86 (as per wesnoth/wesnoth#9284 (comment)).

Any advice, please?

[Osyotr]

Minimal reproducer: https://godbolt.org/z/6c1PWMsb3
jgaa/restc-cpp#160

[Wedge009]

Thank you for that!

[Wedge009]

Reviewing the documentation for the function as of boost 1.80 does indeed state that the form without a completion token is supposed to be deprecated. Perhaps this isn't exactly the behaviour that's desired for boost, but it does indicate the intention is for the completion token to be explicitly given.