On 29/10/20 19:48 -0400, Patrick Palka via Libstdc++ wrote:
On Thu, 29 Oct 2020, Patrick Palka wrote:The class template semiregular-box<T> of [range.semi.wrap] is specified to value-initialize the underlying object whenever its type is default- initializable. Our primary template for __detail::__box respects this requirement, but the recently added partial specialization (for types which are already semiregular) does not. This patch fixes this issue, and additionally makes the in place constructor explicit (as in the primary template). Tested on x86_64-pc-linux-gnu, does this look OK for trunk? libstdc++-v3/ChangeLog: * include/std/ranges (__detail::__box): For the partial specialization for types that are already semiregular, make the default constructor value-initialize the underlying object instead of default-initializing it. Make the corresponding in place constructor explicit. * testsuite/std/ranges/detail/semiregular_box.cc: New test. --- libstdc++-v3/include/std/ranges | 4 +-- .../std/ranges/detail/semiregular_box.cc | 33 +++++++++++++++++++ 2 files changed, 35 insertions(+), 2 deletions(-) create mode 100644 libstdc++-v3/testsuite/std/ranges/detail/semiregular_box.cc diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index df02b03cada..59aac326309 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -141,7 +141,7 @@ namespace ranges struct __box<_Tp> { private: - [[no_unique_address]] _Tp _M_value; + [[no_unique_address]] _Tp _M_value = {};It would be more consistent with the rest of the header to do = _Tp() instead:
OK, thanks.
