https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124347
--- Comment #7 from Tomasz Kamiński <tkaminsk at gcc dot gnu.org> ---
Clang only fails on string literals, i.e. for the line in the original example:
static_assert (foo ("foo") == 4);
This does not prevent me from using it for the output of format_to, as you
cannot print into string literals (they are const), so I do not need workaround
for the use case.
See https://github.com/llvm/llvm-project/pull/196377.
