https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112632
Bug ID: 112632
Summary: [14 Regression] Non-type template parameter created
with converting constructor sometimes has original
type
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: needs-bisection, rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
template<typename T>
inline constexpr bool C = true;
struct n {
constexpr n(int a) : i(a) {}
int i;
};
template<n N>
using get_n_i_type = decltype(N.i);
template<int X>
int f() {
using iii = get_n_i_type<X>;
#if 1 // Change to 0 and this compiles
static_assert(C<iii>);
#endif
return iii{};
}
template int f<3>();
```
This is rejected on the trunk with:
```
<source>: In instantiation of 'int f() [with int X = 3]':
<source>:22:23: required from here
22 | template int f<3>();
| ^
<source>:11:37: error: request for member 'i' in '3', which is of non-class
type 'int'
11 | using get_n_i_type = decltype(N.i);
| ~~^
```
But was accepted in GCC 13. Note the difference between this and PR 112594 is
that C here is declared an `inline constexpr` rather than a concept.
