Compilation failure when converting decimal to string with {fmt} and FMT_COMPILE #1537

After the commits of PR #1536, the following fails to compile on VS2026 18.11.2:

void DecimalToString(decimal64_t x, wchar_t *s, size_t size)
{
	if (s != nullptr && size > 0)
	{
		auto r = fmt::format_to_n(s, size - 1, FMT_COMPILE(L"{}"), x);
		*r.out = L'\0';
	}
}

Error C2679 binary '=': no operator found which takes a right-hand operand of type 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' (or there is no acceptable conversion) D:\x\Include\boost\decimal\detail\format_render.hpp 246

Removing FMT_COMPILE works. So does std::format_to_n().

Nonetheless, the following compiles:

std::wstring DecimalToString(decimal64_t x)
{
	return fmt::format(FMT_COMPILE(L"{}"), x);
}

Would this be an issue in Boost.Decimal or {fmt}?

Many thanks for your excellent library!