D473 - A C++ throw with no unwinder is a named stop, not a return

Status: assumed Date: 2026-09-02

Every guest entry point whose sole purpose is to raise a C++ exception reports which exception was thrown, with its message, and ends the run there, rather than returning to the caller.

Why: the caller's code was generated on the promise that the call does not return, so returning would continue execution at a point the guest's own compiler proved unreachable. Stopping cannot deliver the exception to a handler the guest may have had, but it is a legible gap rather than a silent wrong continuation.

Rejected:

• Returning a placeholder and letting the guest continue: keeps the guest alive but resumes it at a point proven unreachable, with no visible relationship between the throw and the eventual failure.