Scope failure is not preventing application crush in case of uncaught exceptions

[Jonathan M Davis]

On Sunday, December 17, 2017 08:10:06 codephantom via Digitalmars-d-learn 
wrote:
> On Sunday, 17 December 2017 at 00:10:27 UTC, Anonymouse wrote:
> > If you return inside a scopeguard though, the exception (or
> > error!) is swallowed. https://run.dlang.io/is/GEtQ6D
>
> The scope guard will not 'swallow' it, if you use -release mode.
>
> Which suggests to me, that assert(0) operates differently when
> 'not' using -release mode.
>
> My 'guess' is, that release mode issues a halt instruction,
> whereas in non-release mode it is just an exception like any
> other exception.

assert(0) does indeed turn into a HLT instruction in -release mode (as does
any assertion that's known to be false at compile time). It's a special case
intended for marking code that's supposed to be unreachable. Without
-release, failed assertions throw AssertErrors, so they're Errors not
Exceptions, though I think that scope statements currently catch and then
rethrow Throwable rather than Exception, which is why AssertErrors would be
affected.

- Jonathan M Davis