[mehrdadn]

> It's clearly possible for C++ compilers to do this in many more cases. [...] Why not use that knowledge more often to help the programmer instead of burdening them?

Because it'd break code. I explained in another comment here: https://news.ycombinator.com/item?id=19634423

[notacoward]

> Because it'd break code.

Then that's an indictment of the decisions that led to such code being written in the first place.

[mehrdadn]

Only if you're quick to judge without understanding why such code is and will continue to be written.

[notacoward]

You're pretty quick to assume I don't. Believe me, I understand. I just don't agree that it's a good idea to mix up object lifetimes and execution context by using destructors to "magically" release locks etc. It never was. The mistakes were made years ago.

I'm not quick to judge (in this case). I'm judging after careful consideration, because I know the difference between good and bad patterns. The ones being hasty are those who mistake their own comfort level with something (often because they know nothing else) for actual merit.

[j16sdiz]

RAII is one of the core language feature of C++.

Replacing it with defer or GC will surely break existing programs.

It would make sense ONLY if you want to have a new language.

[notacoward]

> It would make sense ONLY if you want to have a new language.

Are you seriously suggesting that C++ with defer is a new language? Unlike, say, C++ with lambdas? That's just silly.

[klmr]

C++ without deterministic destructors to manage lifetime would be a (fundamentally) different language.

Furthermore, also disagree with you that it would be a better language. C++ has many warts but object lifetime and RAII is amongst its strong suits (unarguably, I thought — yes, resource lifetime is complex, but it’s inherently so; C++ just makes the complexity explicit and handles it in a good way). Handling resource lifetime in languages with nondeterministic GCs can be such a pain that it has fundamental, detrimental impact on the architecture. Just look at .NET’s handling of `Dispose`. I’ve written a ton of .NET GUI code, and handling resource lifetime (in particular GDI+) is an absolute pain point, which is uniquely caused by the lack of deterministic object lifetime.

[mehrdadn]

Your proposed better pattern to follow when one needs a finally block in C++ is...?

[notacoward]

I already mentioned "defer" as in Go or Zig. It's explicitly tied to scope exit, not object lifetime, so it avoids all of the problems inherent in confusing the two.

[mehrdadn]

I didn't ask what language you would use. I asked what you would do in C++, given you're criticizing people for writing such code in the language. If you're put so much thought into this problem like you claim then surely you must have a better alternative in mind.