What is the point of nothrow?

[Kagamin]

On Friday, 15 June 2018 at 17:46:02 UTC, wjoe wrote:
>> D allows various levels of performance and safety. Though I'd 
>> say Errors not working in debug mode is not intended, the
>
> Intention matters not. By definition all program state is 
> invalid at the point an Error was thrown. From there on it is 
> impossible to rely on any output, too, because it could be 
> either correct, corrupted, or completely invalid.

The program is in invalid state when it hits a bug before Error 
is thrown, this is seen as a property of a buggy algorithm, Error 
is thrown only as a diagnostic of a bug that has happened 
already. The state is invalid in a sense that the program 
shouldn't continue to serve its intended purpose. Even if Error 
was technically correctly unwound, it won't necessarily provide a 
correct cleanup when algorithm doesn't expect an exception.
Though in case of D situation may be not as clear as there is 
safe code, but we just recently had a nasty memory corruption bug 
caused by incorrect trusted code.

> A core dump is created by the OS. In a format that a native 
> debugger understands.

Most of the time a stack trace is enough to diagnose the error 
and provides a better UX than a core dump (especially to 
newbies). I saw gdb crash trying to make sense of a debugged 
program too. Runtime allows to override failure handlers, but 
it's not centralized.