[Bug c++/126643] New: [contracts] ICE on implicit conversion inside template function precondition

[kengusername at proton dot me via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126643

            Bug ID: 126643
           Summary: [contracts] ICE on implicit conversion inside template
                    function precondition
           Product: gcc
           Version: 16.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kengusername at proton dot me
  Target Milestone: ---

This program fails to compile on gcc 16.1 with assertions.


```
template<signed = 0> constexpr auto foo(signed x) pre(x) {}

static_assert((foo(123), 1));
```

https://godbolt.org/z/Yz138x6b8