It doesn't write the accumulator, but it does read it. Generating code
for throwing exceptions reveals that we have to default-construct the
return type rather than converting from undefined/void when throwing an
exception.
Pick-to: 6.2 6.3 6.4
Fixes: QTBUG-104447
Change-Id: I0a725679d8ecb7e87bb20528033097bc0c3c7bb6
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Ulf Hermann