public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument
@ 2022-12-02 17:32 majerech.o at gmail dot com
2022-12-02 20:28 ` [Bug c++/107953] " pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: majerech.o at gmail dot com @ 2022-12-02 17:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107953
Bug ID: 107953
Summary: Greater-than operator misparsed inside a lambda
expression used as a template argument
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: majerech.o at gmail dot com
Target Milestone: ---
template <auto>
void
f() { }
constexpr auto g = f<[] (int x, int y) { return x > y; }>;
This produces the following diagnostic:
<source>: In lambda function:
<source>:5:50: error: expected ';' before '>' token
5 | constexpr auto g = f<[] (int x, int y) { return x > y; }>;
| ^~
| ;
<source>:5:51: error: expected primary-expression before '>' token
5 | constexpr auto g = f<[] (int x, int y) { return x > y; }>;
| ^
ASM generation compiler returned: 1
<source>: In lambda function:
<source>:5:50: error: expected ';' before '>' token
5 | constexpr auto g = f<[] (int x, int y) { return x > y; }>;
| ^~
| ;
<source>:5:51: error: expected primary-expression before '>' token
5 | constexpr auto g = f<[] (int x, int y) { return x > y; }>;
| ^
Godbolt link to the above: https://godbolt.org/z/KG6d5E6ev
Changing the body to return (x > y); makes the error go away as a workaround.
So I speculate that the greater-than operator is misparsed as the end of the
template argument list.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/107953] Greater-than operator misparsed inside a lambda expression used as a template argument
2022-12-02 17:32 [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument majerech.o at gmail dot com
@ 2022-12-02 20:28 ` pinskia at gcc dot gnu.org
2022-12-02 23:18 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-02 20:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107953
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=57
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect this is the same issue as PR 57 .
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/107953] Greater-than operator misparsed inside a lambda expression used as a template argument
2022-12-02 17:32 [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument majerech.o at gmail dot com
2022-12-02 20:28 ` [Bug c++/107953] " pinskia at gcc dot gnu.org
@ 2022-12-02 23:18 ` pinskia at gcc dot gnu.org
2022-12-02 23:23 ` pinskia at gcc dot gnu.org
2022-12-02 23:55 ` majerech.o at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-02 23:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107953
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Even template defaults has issues:
template <auto = [] (int x, int y) { return x > y; }>
int t = 0;
Which is why I Pointed to PR 57.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/107953] Greater-than operator misparsed inside a lambda expression used as a template argument
2022-12-02 17:32 [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument majerech.o at gmail dot com
2022-12-02 20:28 ` [Bug c++/107953] " pinskia at gcc dot gnu.org
2022-12-02 23:18 ` pinskia at gcc dot gnu.org
@ 2022-12-02 23:23 ` pinskia at gcc dot gnu.org
2022-12-02 23:55 ` majerech.o at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-02 23:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107953
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I wonder if this is still an ambiguous part of the C++ grammar and all.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/107953] Greater-than operator misparsed inside a lambda expression used as a template argument
2022-12-02 17:32 [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument majerech.o at gmail dot com
` (2 preceding siblings ...)
2022-12-02 23:23 ` pinskia at gcc dot gnu.org
@ 2022-12-02 23:55 ` majerech.o at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: majerech.o at gmail dot com @ 2022-12-02 23:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107953
--- Comment #4 from Ondřej Majerech <majerech.o at gmail dot com> ---
It seems that the core of PR 57 is that `A<T` could syntactically be a valid
expression, and it would require a look-up to determine that A and T are in
fact a template and a type, and not values.
Here, however, the fragment `[] (int x, int y) { return x` doesn't form a
syntactically valid expression. So, to me at least, it seems there should be no
ambiguity.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-12-02 23:55 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-12-02 17:32 [Bug c++/107953] New: Greater-than operator misparsed inside a lambda expression used as a template argument majerech.o at gmail dot com
2022-12-02 20:28 ` [Bug c++/107953] " pinskia at gcc dot gnu.org
2022-12-02 23:18 ` pinskia at gcc dot gnu.org
2022-12-02 23:23 ` pinskia at gcc dot gnu.org
2022-12-02 23:55 ` majerech.o at gmail dot com
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).