https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109242
Bug ID: 109242
Summary: C++2b std::optional::transform omits required
std::remove_cv_t from return optional type
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: pkasting at google dot com
Target Milestone: ---
The implementation of C++2b's std::optional::transform() on HEAD omits a call
to std::remove_cv_t when determining the value type of the returned optional.
As a result valid code such as the following example is rejected:
https://godbolt.org/z/hG5hnz59e
#include <optional>
struct S {
int i;
};
void foo() {
std::optional<S>().transform(&S::i);
}
Per https://en.cppreference.com/w/cpp/utility/optional/transform, the returned
type should always be computed via std::remove_cv_t<> on the invoke_result, but
per
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libstdc%2B%2B-v3/include/std/optional;hb=HEAD,
_Up consistently omits this.
