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* [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid.
@ 2009-08-02 14:48 v dot haisman at sh dot cvut dot cz
2009-08-04 12:55 ` [Bug c++/40942] " jwakely dot gcc at gmail dot com
` (3 more replies)
0 siblings, 4 replies; 13+ messages in thread
From: v dot haisman at sh dot cvut dot cz @ 2009-08-02 14:48 UTC (permalink / raw)
To: gcc-bugs
The following test case compiles with GCC, it chooses the second ctor. Both
MSVC8 and Comeau reject it complaining about overload ambiguity.
#include <cstdlib>
template <bool B, class T = void>
struct enable_if_c {
typedef T type;
};
template <class T>
struct enable_if_c<false, T> {};
template <class Cond, class T = void>
struct enable_if : public enable_if_c<Cond::value, T> {};
struct true_type
{
enum { value = 1 };
};
struct false_type
{
enum { value = 0 };
};
template <typename T, typename U>
struct is_same
: public false_type
{ };
template <typename T>
struct is_same<T, T>
: public true_type
{ };
struct S
{
template <typename T>
S (T const *,
typename enable_if<is_same<char, T>, T *>::type = 0)
{ }
template <size_t N>
S (char const (&)[N])
{ }
};
int
main()
{
char array[] = "test";
S s1 ("test");
S s2 (array);
}
--
Summary: GCC accepts code that Comeau and MSVC deems invalid.
Product: gcc
Version: 4.4.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: v dot haisman at sh dot cvut dot cz
GCC build triplet: x86_64-portbld-freebsd7.1
GCC host triplet: x86_64-portbld-freebsd7.1
GCC target triplet: x86_64-portbld-freebsd7.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
2009-08-02 14:48 [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid v dot haisman at sh dot cvut dot cz
@ 2009-08-04 12:55 ` jwakely dot gcc at gmail dot com
2009-08-25 13:25 ` bangerth at gmail dot com
` (2 subsequent siblings)
3 siblings, 0 replies; 13+ messages in thread
From: jwakely dot gcc at gmail dot com @ 2009-08-04 12:55 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from jwakely dot gcc at gmail dot com 2009-08-04 12:48 -------
Testcase can be reduced to:
struct S
{
template <typename T>
S (T const *)
{ }
template <size_t N>
S (char const (&)[N])
{ }
};
int
main()
{
S s1 ("test");
}
GCC still accepts this while Comeau rejects it.
--
jwakely dot gcc at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jwakely dot gcc at gmail dot
| |com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
2009-08-02 14:48 [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid v dot haisman at sh dot cvut dot cz
2009-08-04 12:55 ` [Bug c++/40942] " jwakely dot gcc at gmail dot com
@ 2009-08-25 13:25 ` bangerth at gmail dot com
2009-08-25 14:20 ` v dot haisman at sh dot cvut dot cz
2009-08-25 14:49 ` tom at kera dot name
3 siblings, 0 replies; 13+ messages in thread
From: bangerth at gmail dot com @ 2009-08-25 13:25 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from bangerth at gmail dot com 2009-08-25 13:24 -------
Why would this be ambiguous? A string literal has type "array of n const char"
(see 2.13.4/1), so it should go with the array constructor. Do you disagree?
W.
--
bangerth at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bangerth at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
2009-08-02 14:48 [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid v dot haisman at sh dot cvut dot cz
2009-08-04 12:55 ` [Bug c++/40942] " jwakely dot gcc at gmail dot com
2009-08-25 13:25 ` bangerth at gmail dot com
@ 2009-08-25 14:20 ` v dot haisman at sh dot cvut dot cz
2009-08-25 14:49 ` tom at kera dot name
3 siblings, 0 replies; 13+ messages in thread
From: v dot haisman at sh dot cvut dot cz @ 2009-08-25 14:20 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from v dot haisman at sh dot cvut dot cz 2009-08-25 14:20 -------
(In reply to comment #2)
> Why would this be ambiguous? A string literal has type "array of n const char"
> (see 2.13.4/1), so it should go with the array constructor. Do you disagree?
>
> W.
>
IANALL, but I think this might be the reason:
The conversion sequence for S (T const *) is array-to-pointer conversion as per
4.2. The conversion sequence for S (char const (&)[N]) is lvalue-to-rvalue
conversion. For both the ranks are the exact match and thus they are
indistinguishable conversion sequences as per 13.3.3.2?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
2009-08-02 14:48 [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid v dot haisman at sh dot cvut dot cz
` (2 preceding siblings ...)
2009-08-25 14:20 ` v dot haisman at sh dot cvut dot cz
@ 2009-08-25 14:49 ` tom at kera dot name
3 siblings, 0 replies; 13+ messages in thread
From: tom at kera dot name @ 2009-08-25 14:49 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from tom at kera dot name 2009-08-25 14:48 -------
(In reply to comment #2)
> Why would this be ambiguous? A string literal has type "array of n const char"
> (see 2.13.4/1), so it should go with the array constructor. Do you disagree?
>
> W.
>
Table 9 under 13.3.3/1 shows that array-to-pointer conversion is Exact Match.
As is rvalue-to-lvalue conversion (though string literals are lvalues anyway
:D). As is Identity, which is what applies here.
There is no clear ranking between them, hence Comeau reporting ambiguity.
Although I personally think Identity should overrule absolutely everything, it
doesn't. So IMO GCC is buggy in this way.
--
tom at kera dot name changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |tom at kera dot name
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
` (6 preceding siblings ...)
2012-04-02 8:57 ` dodji at gcc dot gnu.org
@ 2021-08-23 7:24 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-23 7:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.8.0
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
` (5 preceding siblings ...)
2012-04-02 8:53 ` dodji at gcc dot gnu.org
@ 2012-04-02 8:57 ` dodji at gcc dot gnu.org
2021-08-23 7:24 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 13+ messages in thread
From: dodji at gcc dot gnu.org @ 2012-04-02 8:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Dodji Seketeli <dodji at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
--- Comment #10 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-04-02 08:56:24 UTC ---
Fixed in 4.8 (trunk).
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2012-03-31 17:07 ` dodji at seketeli dot org
@ 2012-04-02 8:53 ` dodji at gcc dot gnu.org
2012-04-02 8:57 ` dodji at gcc dot gnu.org
2021-08-23 7:24 ` pinskia at gcc dot gnu.org
7 siblings, 0 replies; 13+ messages in thread
From: dodji at gcc dot gnu.org @ 2012-04-02 8:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
--- Comment #9 from Dodji Seketeli <dodji at gcc dot gnu.org> 2012-04-02 08:51:30 UTC ---
Author: dodji
Date: Mon Apr 2 08:51:26 2012
New Revision: 186067
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186067
Log:
PR c++/40942 - Failure of template specialization partial ordering
gcc/cp/
* pt.c (more_specialized_fn): Don't apply decay conversion to
types of function parameters.
gcc/testsuite/
* g++.old-deja/g++.pt/spec40.C: Adjust to take the resolution of
DR 214 in account.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/cp/pt.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/g++.old-deja/g++.pt/spec40.C
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2012-03-30 16:20 ` dodji at gcc dot gnu.org
@ 2012-03-31 17:07 ` dodji at seketeli dot org
2012-04-02 8:53 ` dodji at gcc dot gnu.org
` (2 subsequent siblings)
7 siblings, 0 replies; 13+ messages in thread
From: dodji at seketeli dot org @ 2012-03-31 17:07 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
--- Comment #8 from dodji at seketeli dot org <dodji at seketeli dot org> 2012-03-31 17:02:48 UTC ---
A candidate fix was posted to
http://gcc.gnu.org/ml/gcc-patches/2012-03/msg01993.html for review.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2012-03-29 20:00 ` manu at gcc dot gnu.org
@ 2012-03-30 16:20 ` dodji at gcc dot gnu.org
2012-03-31 17:07 ` dodji at seketeli dot org
` (3 subsequent siblings)
7 siblings, 0 replies; 13+ messages in thread
From: dodji at gcc dot gnu.org @ 2012-03-30 16:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Dodji Seketeli <dodji at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |dodji at gcc dot gnu.org
|gnu.org |
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
2012-03-29 13:43 ` redi at gcc dot gnu.org
2012-03-29 17:53 ` vhaisman at gmail dot com
@ 2012-03-29 20:00 ` manu at gcc dot gnu.org
2012-03-30 16:20 ` dodji at gcc dot gnu.org
` (4 subsequent siblings)
7 siblings, 0 replies; 13+ messages in thread
From: manu at gcc dot gnu.org @ 2012-03-29 20:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |manu at gcc dot gnu.org
--- Comment #7 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-03-29 19:58:34 UTC ---
Clang prints:
/tmp/webcompile/_25725_0.cc:15:5: error: call to constructor of 'S' is
ambiguous
S s1 ("test");
^ ~~~~~~
/tmp/webcompile/_25725_0.cc:4:3: note: candidate constructor [with T = char]
S (T const *)
^
/tmp/webcompile/_25725_0.cc:8:3: note: candidate constructor [with N = 5]
S (char const (&)[N])
^
/tmp/webcompile/_25725_0.cc:1:8: note: candidate is the implicit copy
constructor
struct S
^
1 error generated.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
2012-03-29 13:43 ` redi at gcc dot gnu.org
@ 2012-03-29 17:53 ` vhaisman at gmail dot com
2012-03-29 20:00 ` manu at gcc dot gnu.org
` (5 subsequent siblings)
7 siblings, 0 replies; 13+ messages in thread
From: vhaisman at gmail dot com @ 2012-03-29 17:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Václav Zeman <vhaisman at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Version|4.4.1 |4.7.0
--- Comment #6 from Václav Zeman <vhaisman at gmail dot com> 2012-03-29 17:39:40 UTC ---
This still fails for gcc version 4.7.0 20120225.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug c++/40942] GCC accepts code that Comeau and MSVC deems invalid.
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
@ 2012-03-29 13:43 ` redi at gcc dot gnu.org
2012-03-29 17:53 ` vhaisman at gmail dot com
` (6 subsequent siblings)
7 siblings, 0 replies; 13+ messages in thread
From: redi at gcc dot gnu.org @ 2012-03-29 13:43 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40942
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-03-29
Ever Confirmed|0 |1
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-03-29 13:41:07 UTC ---
confirmed
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2021-08-23 7:24 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-08-02 14:48 [Bug c++/40942] New: GCC accepts code that Comeau and MSVC deems invalid v dot haisman at sh dot cvut dot cz
2009-08-04 12:55 ` [Bug c++/40942] " jwakely dot gcc at gmail dot com
2009-08-25 13:25 ` bangerth at gmail dot com
2009-08-25 14:20 ` v dot haisman at sh dot cvut dot cz
2009-08-25 14:49 ` tom at kera dot name
[not found] <bug-40942-4@http.gcc.gnu.org/bugzilla/>
2012-03-29 13:43 ` redi at gcc dot gnu.org
2012-03-29 17:53 ` vhaisman at gmail dot com
2012-03-29 20:00 ` manu at gcc dot gnu.org
2012-03-30 16:20 ` dodji at gcc dot gnu.org
2012-03-31 17:07 ` dodji at seketeli dot org
2012-04-02 8:53 ` dodji at gcc dot gnu.org
2012-04-02 8:57 ` dodji at gcc dot gnu.org
2021-08-23 7:24 ` pinskia at gcc dot gnu.org
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