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* [Bug c++/95143] New: SFINAE failure with static_cast
@ 2020-05-14 20:13 familiebaumanns at gmail dot com
2020-05-14 20:16 ` [Bug c++/95143] " familiebaumanns at gmail dot com
` (12 more replies)
0 siblings, 13 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:13 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
Bug ID: 95143
Summary: SFINAE failure with static_cast
Product: gcc
Version: 10.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: familiebaumanns at gmail dot com
Target Milestone: ---
Bug 90080 - [8 Regression] SFINAE failure with static_cast
Bug 87748 - [8 Regression] G++-8 treats SFINAE as error
This bug seems to be back in g++-10.1
See the following code: https://godbolt.org/z/yVjQf9
It works in g++-9 and in g++-11 / g++-trunk.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
@ 2020-05-14 20:16 ` familiebaumanns at gmail dot com
2020-05-14 20:18 ` redi at gcc dot gnu.org
` (11 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
Bernd Baumanns <familiebaumanns at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
URL| |https://godbolt.org/z/yVjQf
| |9
--- Comment #1 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
https://godbolt.org/z/FRznAh
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
2020-05-14 20:16 ` [Bug c++/95143] " familiebaumanns at gmail dot com
@ 2020-05-14 20:18 ` redi at gcc dot gnu.org
2020-05-14 20:39 ` familiebaumanns at gmail dot com
` (10 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: redi at gcc dot gnu.org @ 2020-05-14 20:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2020-05-14
Status|UNCONFIRMED |WAITING
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Please read https://gcc.gnu.org/bugs (as requested when creating a bug) and
provide the missing information.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
2020-05-14 20:16 ` [Bug c++/95143] " familiebaumanns at gmail dot com
2020-05-14 20:18 ` redi at gcc dot gnu.org
@ 2020-05-14 20:39 ` familiebaumanns at gmail dot com
2020-05-14 20:42 ` familiebaumanns at gmail dot com
` (9 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #3 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
Created attachment 48541
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48541&action=edit
ii file
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (2 preceding siblings ...)
2020-05-14 20:39 ` familiebaumanns at gmail dot com
@ 2020-05-14 20:42 ` familiebaumanns at gmail dot com
2020-05-14 20:44 ` familiebaumanns at gmail dot com
` (8 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #4 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
Created attachment 48543
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48543&action=edit
g++-10 -v -save-temps -std=c++2a /mnt/j/test.cpp
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (3 preceding siblings ...)
2020-05-14 20:42 ` familiebaumanns at gmail dot com
@ 2020-05-14 20:44 ` familiebaumanns at gmail dot com
2020-05-14 20:53 ` familiebaumanns at gmail dot com
` (7 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #5 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
Created attachment 48544
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48544&action=edit
source
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (4 preceding siblings ...)
2020-05-14 20:44 ` familiebaumanns at gmail dot com
@ 2020-05-14 20:53 ` familiebaumanns at gmail dot com
2020-05-14 20:55 ` familiebaumanns at gmail dot com
` (6 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #6 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
simplified source (without include type_traits):
----------------------------
class false_type
{
public:
static constexpr bool value = false;
};
class true_type{
public:
static constexpr bool value = true;
};
template<class T>
T&& declval() noexcept;
template<typename T, typename U, typename = U>
struct is_static_castable : false_type
{};
template<typename T, typename U>
struct is_static_castable<T, U, decltype(static_cast<U>(declval<T>()))> :
true_type
{};
class Base
{};
struct A
{};
class B: public Base
{};
int main()
{
constexpr auto canCast = is_static_castable<A, B>::value;
static_assert(!canCast);
constexpr auto canCast2 = is_static_castable<A, A>::value;
static_assert(canCast2);
return 0;
}
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (5 preceding siblings ...)
2020-05-14 20:53 ` familiebaumanns at gmail dot com
@ 2020-05-14 20:55 ` familiebaumanns at gmail dot com
2020-05-14 21:08 ` familiebaumanns at gmail dot com
` (5 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 20:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #7 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
I hope you have now all you need.
This bug is only triggered in C++20 mode and with inheritance.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (6 preceding siblings ...)
2020-05-14 20:55 ` familiebaumanns at gmail dot com
@ 2020-05-14 21:08 ` familiebaumanns at gmail dot com
2020-05-14 21:10 ` familiebaumanns at gmail dot com
` (4 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 21:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #8 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
fails with this version:
g++ (Compiler-Explorer-Build) 10.1.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Compiler returned: 0
And this:
g++-10 (Ubuntu 10-20200417-0ubuntu1) 10.0.1 20200417 (experimental) [master
revision a64468a3034:28feadc0609:b835645c7a51b7e99092abe61d677aa491836f95]
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (7 preceding siblings ...)
2020-05-14 21:08 ` familiebaumanns at gmail dot com
@ 2020-05-14 21:10 ` familiebaumanns at gmail dot com
2020-05-14 21:47 ` redi at gcc dot gnu.org
` (3 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: familiebaumanns at gmail dot com @ 2020-05-14 21:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #9 from Bernd Baumanns <familiebaumanns at gmail dot com> ---
fails with this version:
g++-10.1 (GCC) 10.1.0
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (8 preceding siblings ...)
2020-05-14 21:10 ` familiebaumanns at gmail dot com
@ 2020-05-14 21:47 ` redi at gcc dot gnu.org
2020-05-14 22:04 ` redi at gcc dot gnu.org
` (2 subsequent siblings)
12 siblings, 0 replies; 14+ messages in thread
From: redi at gcc dot gnu.org @ 2020-05-14 21:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to fail| |10.1.0
Keywords| |needs-bisection,
| |rejects-valid
Status|WAITING |NEW
Known to work| |10.1.1, 11.0, 9.2.0
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Thanks. Confirmed as a bug in 10.1 but it already seems to be fixed on the
gcc-10 branch after the release. I'll bisect it.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (9 preceding siblings ...)
2020-05-14 21:47 ` redi at gcc dot gnu.org
@ 2020-05-14 22:04 ` redi at gcc dot gnu.org
2020-05-15 7:26 ` rguenth at gcc dot gnu.org
2020-05-18 17:53 ` cvs-commit at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: redi at gcc dot gnu.org @ 2020-05-14 22:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Possibly fixed as part of PR 94885.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (10 preceding siblings ...)
2020-05-14 22:04 ` redi at gcc dot gnu.org
@ 2020-05-15 7:26 ` rguenth at gcc dot gnu.org
2020-05-18 17:53 ` cvs-commit at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-05-15 7:26 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
CC| |mpolacek at gcc dot gnu.org
Status|NEW |RESOLVED
--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
Thus fixed. Adding the testcase might be nice.
^ permalink raw reply [flat|nested] 14+ messages in thread
* [Bug c++/95143] SFINAE failure with static_cast
2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
` (11 preceding siblings ...)
2020-05-15 7:26 ` rguenth at gcc dot gnu.org
@ 2020-05-18 17:53 ` cvs-commit at gcc dot gnu.org
12 siblings, 0 replies; 14+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-05-18 17:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95143
--- Comment #13 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:
https://gcc.gnu.org/g:be464161b4ae128681958d94aa460531cf30e0a4
commit r11-459-gbe464161b4ae128681958d94aa460531cf30e0a4
Author: Marek Polacek <polacek@redhat.com>
Date: Mon May 18 13:50:39 2020 -0400
c++: Add test for c++/95143
Already fixed by r10-8124-gceae6a13366d9646e172fc943fe8e221b70f0920.
PR c++/95143
* g++.dg/cpp0x/sfinae66.C: New test.
^ permalink raw reply [flat|nested] 14+ messages in thread
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2020-05-14 20:13 [Bug c++/95143] New: SFINAE failure with static_cast familiebaumanns at gmail dot com
2020-05-14 20:16 ` [Bug c++/95143] " familiebaumanns at gmail dot com
2020-05-14 20:18 ` redi at gcc dot gnu.org
2020-05-14 20:39 ` familiebaumanns at gmail dot com
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2020-05-14 21:10 ` familiebaumanns at gmail dot com
2020-05-14 21:47 ` redi at gcc dot gnu.org
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