scope guards

[David Nadlinger via Digitalmars-d]

On Saturday, 9 August 2014 at 11:51:06 UTC, Idan Arye wrote:
> On Saturday, 9 August 2014 at 00:17:07 UTC, Jonathan M Davis 
> wrote:
>> I suspect that it says that because someone complained about 
>> the error talking about finally when they had used scope(exit) 
>> and not finally. The fact that scope statements get lower to 
>> try-catch-finally blocks allow for a few screwy things that 
>> were not intended. Whether those things will be left in or 
>> made illegal at this point is another matter, but I'm sure 
>> that it was never the intention that anyone be allowed to 
>> return from any kind of scope statement or do anything else 
>> which would cause the exception to not be rethrown.
>>
>> - Jonathan M Davis
>
> If that was the case, the error would have said it's illegal to 
> throw from "finally or scope bodies". The fact that it 
> specifically specifies `scope(exit)` and `scope(success)` and 
> leave out `scope(failure)` means that whoever wrote that error 
> message made a conscious decision that it's OK to return in 
> `scope(failure)`.

Nope. The current wording of the error message resp. the source 
code for handling it simply resulted from a conservative fix for 
rewrite internals being leaked into the diagnostics: 
https://issues.dlang.org/show_bug.cgi?id=6889

In other words, nobody made a "conscious decision" that it is 
okay to return in scope(failure). It's just a consequence from 
the fact that it is rewritten into a catch block instead of 
finally {} like the others.

Cheers,
David