public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/95944] New: Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly
@ 2020-06-28 2:23 barry.revzin at gmail dot com
2020-06-28 7:57 ` [Bug c++/95944] " ensadc at mailnesia dot com
2020-06-29 12:54 ` ppalka at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: barry.revzin at gmail dot com @ 2020-06-28 2:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95944
Bug ID: 95944
Summary: Concept diagnostic has multiple copies of irrelevant
type and displays correct type incorrectly
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: barry.revzin at gmail dot com
Target Milestone: ---
Consider the following heavily reduced, and incorrect, attempt at an iterator:
#include <ranges>
template <typename T>
struct range {
struct iterator {
using reference = T;
using value_type = T;
auto operator*() -> T;
};
};
static_assert(std::indirectly_readable<range<int>::iterator>);
This fails to meet the requirements of indirectly_readable because operator*()
needs to be const. This is the diagnostic I get from gcc trunk:
source>:13:20: error: static assertion failed
13 | static_assert(std::indirectly_readable<range<int>::iterator>);
| ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:13:20: note: constraints not satisfied
In file included from
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/stl_iterator_base_types.h:71,
from
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/iterator:61,
from
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/ranges:44,
from <source>:1:
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:446:13:
required for the satisfaction of '__indirectly_readable_impl<typename
std::remove_cv<typename std::remove_reference<_Tp>::type>::type>' [with _Tp =
range<int>::iterator<int>]
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:446:42:
in requirements with 'const _In __in' [with _Tp = range<int>::iterator<int>;
_Tp = range<int>::iterator<int>; _In = range<int>::iterator<int>]
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:451:4:
note: the required expression '* __in' is invalid
451 | { *__in } -> same_as<iter_reference_t<_In>>;
| ^~~~~
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:452:21:
note: the required expression 'std::ranges::__cust::iter_move(__in)' is invalid
452 | { ranges::iter_move(__in) } -> same_as<iter_rvalue_reference_t<_In>>;
| ~~~~~~~~~~~~~~~~~^~~~~~
cc1plus: note: set '-fconcepts-diagnostics-depth=' to at least 2 for more
detail
Compiler returned: 1
There are two especially important lines in this diagnostic: the one that
indicates the failed expression and the one that indicates the type of it. The
one that indicates the types is this one:
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:446:42:
in requirements with 'const _In __in' [with _Tp = range<int>::iterator<int>;
_Tp = range<int>::iterator<int>; _In = range<int>::iterator<int>]
There is only one type in the requirement (_In) but the description starts with
some type _Tp. And then we get _Tp a second time, before finally getting to
_In. _In is also displayed incorrectly: it is shown as
range<int>::iterator<int> when it should be range<int>::iterator.
Ideally this line looks closer to:
/opt/compiler-explorer/gcc-10.1.0/include/c++/10.1.0/bits/iterator_concepts.h:446:42:
in requirements with 'const _In __in' [with _In = range<int>::iterator]
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/95944] Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly
2020-06-28 2:23 [Bug c++/95944] New: Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly barry.revzin at gmail dot com
@ 2020-06-28 7:57 ` ensadc at mailnesia dot com
2020-06-29 12:54 ` ppalka at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: ensadc at mailnesia dot com @ 2020-06-28 7:57 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95944
ensadc at mailnesia dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ensadc at mailnesia dot com
--- Comment #1 from ensadc at mailnesia dot com ---
bug95303, bug95310
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/95944] Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly
2020-06-28 2:23 [Bug c++/95944] New: Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly barry.revzin at gmail dot com
2020-06-28 7:57 ` [Bug c++/95944] " ensadc at mailnesia dot com
@ 2020-06-29 12:54 ` ppalka at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: ppalka at gcc dot gnu.org @ 2020-06-29 12:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95944
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-06-29
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
CC| |ppalka at gcc dot gnu.org
--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-06-29 12:54 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-28 2:23 [Bug c++/95944] New: Concept diagnostic has multiple copies of irrelevant type and displays correct type incorrectly barry.revzin at gmail dot com
2020-06-28 7:57 ` [Bug c++/95944] " ensadc at mailnesia dot com
2020-06-29 12:54 ` ppalka at gcc dot gnu.org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).