The expression of static_assert is not an immediate function context

[JohelEGP]

See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106485#c2.

See https://godbolt.org/z/4GMxo13vv.

#include <string>
consteval auto s() { return std::string(); }
static_assert(s().empty()); // Only Clang accepts.
// static_assert([]() consteval { return s().empty(); }()); // All accept.
// static_assert([]() { return s().empty(); }()); // All reject.

I think static_assert(s().empty()); should also be rejected by Clang.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[shafik]

If we look at:

constexpr auto y = s().empty();

it feels like clang is not being consistent. Either s().empty() is a constant expression or not.

[AaronBallman]

It seems MSVC also accepts what Clang accepts, while ICC rejects the same way GCC does.

[cor3ntin]

All compilers now accept all 4 static_asserts https://godbolt.org/z/naeoWYfWq
Clang was changed in 17.0