https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103852
Bug ID: 103852
Summary: Alias template argument deduction is available in
C++17 mode
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
This is a valid C++20 code:
```
#include <set>
template<class Key, class Compare = std::less<Key>, class Allocator =
std::allocator<Key>>
using Set = std::set<Key, Compare, Allocator>;
int main() {
Set set2 = { 1, 2, 3 };
}
```
But in C++17 mode it shall be an error, since alias template argument deduction
is not available there. Still GCC wrongly accepts the code in C++17 mode. Demo:
https://gcc.godbolt.org/z/f5WbWdPqb
Related discussion: https://stackoverflow.com/q/68768937/7325599
