https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108364
Bug ID: 108364
Summary: Construction from prvalue erroneously uses
move-constructor
Product: gcc
Version: 12.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
In the following code Bar default-constructor initializes its unmovable parent
Foo using a conversion operator creating a prvalue:
struct Foo {
Foo() = default;
Foo(Foo const&) = delete;
Foo(Foo&&) = delete;
};
Foo foo() { return {}; }
template<typename F>
struct call_wrapper {
F&& f;
constexpr operator decltype(auto)() && {
return static_cast<F&&>(f)();
}
};
template<typename F>
call_wrapper(F&&) -> call_wrapper<F>;
struct Bar : Foo {
Bar() : Foo(call_wrapper{foo}) {}
};
It works in Clang and MSVC, but unfortunately not in GCC, which prints
error: use of deleted function 'Foo::Foo(Foo&&)
Online demo: https://gcc.godbolt.org/z/3Wfdfb36a
This type of object construction was recommended in
https://stackoverflow.com/a/75068264/7325599
