https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82745
--- Comment #6 from helge at penne dot no --- I'm sorry if I confused you by using the wrong terminology here. My bad. We're now getting to the real issue, and that's great. You're right that C++ by default allows implicit conversion that loose precision, but there is an option to enable warnings on this, and the bug I want to report is that this does not work as it should. Some important cases are not detected. The problem is that "auto foo = std::make_unique<Foo>(1000u);" from the example does not result in any warning. However, using unique_ptr and new does. This is unexpected and inconsistent. Similarly, the example from the standards forum shows that similar problems exist when initialising std::pair. I'v also found that the compiler does not warn on loss of precision in calls to "emplace": vector<char> v; v.emplace_back(1000); // No warning v.push_back(1000); // Warning All this is very bad when you're writing secure code. I'm sure you're right in your analysis about why this happens. The problem is that it really should not behave in this way. The compiler needs to consistently warn about loss of precision if configured to do so.
