https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117855
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2024-11-30
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reduced testcase:
```
template <typename T, int _Extent = -1> struct span { span(T&&);};
template <typename T> span(T &&) -> span<T>;
template <typename et, int e = -1>
struct this_span : span<et, e> {
using span<et, e>::span;
};
template <typename T> this_span(T &&) -> this_span<T>;
int vec;
this_span a = vec;
```
The deduction guides for both this_span and span is required to have this as
valid code. Without the deduction guide for this_span, GCC still crashes.
Without the deduction guide for span, GCC works.
Without the default template arguments, GCC works too.
