[Bug c++/119503] New: Error on decltype of lambda expression in variadic NTTP

[eczbek.void at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119503

            Bug ID: 119503
           Summary: Error on decltype of lambda expression in variadic
                    NTTP
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eczbek.void at gmail dot com
  Target Milestone: ---

https://godbolt.org/z/MfEqT64an

```cpp
template<decltype([] {})...> int x;

int main() {}
```

```
<source>:1:19: error: lambda-expression in template parameter type
    1 | template<decltype([] {})...> int x;
      |                   ^
```