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* [Bug c++/108114] New: Designated initialization of parent class results in error in C++20 mode
@ 2022-12-14 20:06 gawain.bolton at free dot fr
2022-12-14 20:14 ` [Bug c++/108114] " pinskia at gcc dot gnu.org
2022-12-14 20:16 ` pinskia at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: gawain.bolton at free dot fr @ 2022-12-14 20:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108114
Bug ID: 108114
Summary: Designated initialization of parent class results in
error in C++20 mode
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gawain.bolton at free dot fr
Target Milestone: ---
Created attachment 54095
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54095&action=edit
Code accepted with -std=c++17 and rejected with -std=c++20
The attached code generates the following error when compiled with -std=c++20:
<source>: In function 'int main()':
<source>:11:19: error: either all initializer clauses should be designated or
none of them should be
11 | B b{{.a = 0}, .b = 1};
| ^
From my understanding of the C++20 standard (cf.
https://eel.is/c++draft/dcl.init.general#nt:brace-or-equal-initializer)
this code attached is valid since a designated-initializer-clause may be a
braced-init-list.
This code has no error or warning about designated initialization with
-std=c++17
Clang generates a warning about mixed designated/non-designated initialization,
which I believe is not merited, but this is not an error.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/108114] Designated initialization of parent class results in error in C++20 mode
2022-12-14 20:06 [Bug c++/108114] New: Designated initialization of parent class results in error in C++20 mode gawain.bolton at free dot fr
@ 2022-12-14 20:14 ` pinskia at gcc dot gnu.org
2022-12-14 20:16 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-14 20:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108114
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
clang gives:
<source>:11:19: warning: mixture of designated and non-designated initializers
in the same initializer list is a C99 extension [-Wc99-designator]
B b{{.a = 0}, .b = 1};
^~~~~~
<source>:11:9: note: first non-designated initializer is here
B b{{.a = 0}, .b = 1};
^~~~~~~~
With -std=c++17 -pedantic GCC produces:
<source>: In function 'int main()':
<source>:11:10: warning: C++ designated initializers only available with
'-std=c++20' or '-std=gnu++20' [-Wc++20-extensions]
11 | B b{{.a = 0}, .b = 1};
| ^
<source>:11:19: warning: C++ designated initializers only available with
'-std=c++20' or '-std=gnu++20' [-Wc++20-extensions]
11 | B b{{.a = 0}, .b = 1};
| ^
In GCC 7 (and before) -std=c++17 -pedantic GCC gives:
<source>: In function 'int main()':
<source>:11:9: warning: ISO C++ does not allow C99 designated initializers
[-Wpedantic]
B b{{.a = 0}, .b = 1};
^
<source>:11:17: warning: ISO C++ does not allow C99 designated initializers
[-Wpedantic]
B b{{.a = 0}, .b = 1};
^
Most likely just a difference between C99 and C++20 support.
Also note "but this is not an error" is because if you use -pedantic-errors you
would get an error with clang and even GCC with -std=c++17.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/108114] Designated initialization of parent class results in error in C++20 mode
2022-12-14 20:06 [Bug c++/108114] New: Designated initialization of parent class results in error in C++20 mode gawain.bolton at free dot fr
2022-12-14 20:14 ` [Bug c++/108114] " pinskia at gcc dot gnu.org
@ 2022-12-14 20:16 ` pinskia at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-12-14 20:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108114
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Gawain Bolton from comment #0)
> From my understanding of the C++20 standard (cf.
> https://eel.is/c++draft/dcl.init.general#nt:brace-or-equal-initializer)
> this code attached is valid since a designated-initializer-clause may be a
> braced-init-list.
https://eel.is/c++draft/dcl.init.general#nt:braced-init-list shows that
intermixing them is not allowed.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-12-14 20:06 [Bug c++/108114] New: Designated initialization of parent class results in error in C++20 mode gawain.bolton at free dot fr
2022-12-14 20:14 ` [Bug c++/108114] " pinskia at gcc dot gnu.org
2022-12-14 20:16 ` pinskia at gcc dot gnu.org
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