https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95287
Bug ID: 95287
Summary: Incorrect default argument checking for
specializations of functions with parameter packs
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: raul at tambre dot ee
Target Milestone: ---
template<class... Ts>
void j(int i = 0, Ts... ts) {}
template<>
void j<int>(int i, int j) {}
Fails to compile with:
<source>:5:24: error: default argument missing for parameter 2 of 'void j(int,
Ts ...) [with Ts = {int}]'
5 | void j<int>(int i, int j) {}
| ~~~~^
<source>:5:17: note: ...following parameter 1 which has a default argument
5 | void j<int>(int i, int j) {}
| ~~~~^
This is valid code.
Possibly related to DR2233[0], which supersedes DR777[1].
MSVC and ICC accept this code.
Clang has a patch in review to implement DR2233[2].
[0] http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#2233
[1] http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#777
[2] https://reviews.llvm.org/D79800
