If the move can fail, so can most likely the copy. Use of
move_if_noexcept() therefore trades a faster potentially-throwing
operation for a slower potentially-throwing operation.
It is true that a throwing move ctor may leave the source object in a
partially-formed state while the copy ctor may not (exceptions prove
the rule, hello auto_ptr), but we shouldn't pessimize lazy coders
(missing noexcept) to cater for borderline-buggy code (throwing move
ctor that doesn't provide the strong exception guarantee). Yes, you
can construct such situations (and something as simple as
std::array<std::pmr::string, 10> is already affected), but we don't
cater for these anywhere else in Qt, so why do it here?
Change-Id: I728af8e87ed86f24326530f704a48df1f728ac98
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
b2bcf3b68a