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* [Bug c++/102157] New: floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression
@ 2021-09-01 7:35 xmh970252187 at gmail dot com
2021-09-01 22:07 ` [Bug c++/102157] " pinskia at gcc dot gnu.org
2021-09-02 3:11 ` xmh970252187 at gmail dot com
0 siblings, 2 replies; 3+ messages in thread
From: xmh970252187 at gmail dot com @ 2021-09-01 7:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102157
Bug ID: 102157
Summary: floating-integral conversions is not permitted in the
user-defined conversion sequence in converted constant
expression
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: xmh970252187 at gmail dot com
Target Milestone: ---
struct A{
constexpr A(double const& rf){}
};
template<class T, T B>
struct C{};
int main() {
C<A,0> b;
}
This code is accepted by GCC while rejected by Clang.
[temp.arg.nontype] p2
> A template-argument for a non-type template-parameter shall be a converted constant expression ([expr.const]) of the type of the template-parameter.
>From a prvalue of type `int` to type `A`, the user-defined conversion sequence
will involve floating-integral conversions that are not permitted in
[expr.const] p10. GCC should reject this example.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/102157] floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression
2021-09-01 7:35 [Bug c++/102157] New: floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression xmh970252187 at gmail dot com
@ 2021-09-01 22:07 ` pinskia at gcc dot gnu.org
2021-09-02 3:11 ` xmh970252187 at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-09-01 22:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102157
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2021-09-01
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There are two issues here really (both accepts invalid).
First is binding to a temp is invalid:
struct A{
constexpr A(double const &rf){}
};
template<class T, T B>
struct C{};
int main() {
C<A,0.> b;
}
----- CUT ----
Second is the conversion is also invalid:
struct A{
constexpr A(double rf){}
};
template<class T, T B>
struct C{};
int main() {
C<A,0> b;
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/102157] floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression
2021-09-01 7:35 [Bug c++/102157] New: floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression xmh970252187 at gmail dot com
2021-09-01 22:07 ` [Bug c++/102157] " pinskia at gcc dot gnu.org
@ 2021-09-02 3:11 ` xmh970252187 at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: xmh970252187 at gmail dot com @ 2021-09-02 3:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102157
--- Comment #2 from jim x <xmh970252187 at gmail dot com> ---
bind the temporary is permitted here to me. Since the template parameter is not
a reference type, there is no restriction on whether a temporary object is
generated in the implicit conversion.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-09-02 3:11 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-01 7:35 [Bug c++/102157] New: floating-integral conversions is not permitted in the user-defined conversion sequence in converted constant expression xmh970252187 at gmail dot com
2021-09-01 22:07 ` [Bug c++/102157] " pinskia at gcc dot gnu.org
2021-09-02 3:11 ` xmh970252187 at gmail dot com
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