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* [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted
@ 2015-03-04 12:10 radventure at yandex dot ru
2015-03-04 12:16 ` [Bug c++/65312] " redi at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: radventure at yandex dot ru @ 2015-03-04 12:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65312
Bug ID: 65312
Summary: Implicitly-declared default constructor must be
defined as deleted
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: radventure at yandex dot ru
I think the next code should not be successfully compiled because of
implicitly-declared default constructor of Array struct should be deleted
#include <cstdint>
#include <iostream>
constexpr uint64_t Fib(uint32_t i)
{
return (i < 2)? i: (Fib(i - 1) + Fib(i - 2));
}
template <uint32_t Z, uint32_t N> struct List
{
const uint64_t val = Fib(Z - N);
List<Z, N - 1> next;
};
template <uint32_t Z> struct List<Z, 0>
{
const uint64_t value = Fib(Z - 0);
};
template <uint32_t Z> struct Array
{
const List<Z - 1, Z - 1> data;
const uint64_t *table = reinterpret_cast<const uint64_t*>(&data);
constexpr uint32_t size() const { return Z; }
};
Array<20u> array;
int main()
{
for (uint32_t i(0); i < array.size(); ++i)
std::cout << array.table[i] << " ";
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/65312] Implicitly-declared default constructor must be defined as deleted
2015-03-04 12:10 [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted radventure at yandex dot ru
@ 2015-03-04 12:16 ` redi at gcc dot gnu.org
2015-03-04 12:41 ` radventure at yandex dot ru
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: redi at gcc dot gnu.org @ 2015-03-04 12:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65312
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I believe this is a GCC extension, G++ implements the proposed resolution of
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253 and since all
sub-objects of List are correctly initialized, no initializer is required for
the member of that type.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/65312] Implicitly-declared default constructor must be defined as deleted
2015-03-04 12:10 [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted radventure at yandex dot ru
2015-03-04 12:16 ` [Bug c++/65312] " redi at gcc dot gnu.org
@ 2015-03-04 12:41 ` radventure at yandex dot ru
2015-03-16 10:50 ` mpolacek at gcc dot gnu.org
2015-03-17 9:47 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: radventure at yandex dot ru @ 2015-03-04 12:41 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65312
--- Comment #2 from radventure at yandex dot ru ---
(In reply to Jonathan Wakely from comment #1)
> I believe this is a GCC extension, G++ implements the proposed resolution of
> http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253 and since
> all sub-objects of List are correctly initialized, no initializer is
> required for the member of that type.
Ok. Other question on a little bit another code. Why generated output so
dramatically changed when I removed initializer of 'data' member of Array
struct (//Here commented)
#include <cstdint>
#include <iostream>
constexpr uint64_t Fib(uint32_t i)
{
return (i < 2)? i: (Fib(i - 1) + Fib(i - 2));
}
template <uint32_t Z, uint32_t N> struct List
{
const uint64_t val = Fib(Z - N);
const List<Z, N - 1> next{};
};
template <uint32_t Z> struct List<Z, 0>
{
const uint64_t value = Fib(Z - 0);
};
template <uint32_t Z> struct Array
{
const List<Z - 1, Z - 1> data{}; //Here
const uint64_t *table = reinterpret_cast<const uint64_t*>(&data);
constexpr uint32_t size() const { return Z; }
};
Array<20u> array;
int main()
{
for (uint32_t i(0); i < array.size(); ++i)
std::cout << array.table[i] << " ";
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/65312] Implicitly-declared default constructor must be defined as deleted
2015-03-04 12:10 [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted radventure at yandex dot ru
2015-03-04 12:16 ` [Bug c++/65312] " redi at gcc dot gnu.org
2015-03-04 12:41 ` radventure at yandex dot ru
@ 2015-03-16 10:50 ` mpolacek at gcc dot gnu.org
2015-03-17 9:47 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-03-16 10:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65312
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mpolacek at gcc dot gnu.org
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Looks like this PR could be resolved as a NOTABUG?
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/65312] Implicitly-declared default constructor must be defined as deleted
2015-03-04 12:10 [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted radventure at yandex dot ru
` (2 preceding siblings ...)
2015-03-16 10:50 ` mpolacek at gcc dot gnu.org
@ 2015-03-17 9:47 ` mpolacek at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2015-03-17 9:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65312
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |INVALID
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Closing then.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2015-03-17 9:47 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2015-03-04 12:10 [Bug c++/65312] New: Implicitly-declared default constructor must be defined as deleted radventure at yandex dot ru
2015-03-04 12:16 ` [Bug c++/65312] " redi at gcc dot gnu.org
2015-03-04 12:41 ` radventure at yandex dot ru
2015-03-16 10:50 ` mpolacek at gcc dot gnu.org
2015-03-17 9:47 ` mpolacek at gcc dot gnu.org
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