Valid code fails with "reference to local variable declared in enclosing function"

[Ignition]

#include <array>
#include <ranges>

int main() {
    constexpr auto v = std::array{1, 2, 3, 4, 5, 6};
    for (auto const& [t0, t1, t2] : v | std::views::adjacent<3>) {
    }
}

error: reference to local variable 'v' declared in enclosing function 'main'

Works in GCC 15.1
Error in clang 20.1.0
Works if you remove constexpr

godbolt link

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Gareth Andrew Lloyd (Ignition)

```cpp #include <array> #include <ranges>

int main() {
constexpr auto v = std::array{1, 2, 3, 4, 5, 6};
for (auto const& [t0, t1, t2] : v | std::views::adjacent<3>) {
}
}

> error: reference to local variable 'v' declared in enclosing function 'main'

Works in GCC 15.1
Error in clang 20.1.0
Works if you remove constexpr

[godbolt link](https://godbolt.org/z/7d3aW5Y4b)
</details>

[shafik]

These look like duplicates: #140622

If you think there is a difference then we would need a reduction to verify it.

[shafik]

@Endilll I think it might be worth it to get a reduction for this, to see if it ends up being a different test case once it is minimal than the other cases.

[cor3ntin]

@shafik I did check that this code was fixed by #140699

[shafik]

@shafik I did check that this code was fixed by #140699

yeah, I want to see if the reduction yields a significantly different test case, so we can expand coverage but maybe it just boils down to the same code.