safe pure nothrow sort and sum

[monarchdodra]

Since @9rnsr fixed 12542, it is now possible to have pure/nothrow/safe sort and sum. sum needed no work done, so I just went and made the marked unittests so as to cover the inference.

sort was a bit harder. I had to strip some formatting in error handling, so as to make the code nothrow (no big loss here I think). I also had to work a bit around 12410.

I'm not sure sort is quite as safe/pure/nothrow as it could be for every type (I haven't done too much checks), but at the very least, it is for PODs inside arrays, with predicates. That's already pretty good.

That's it.

@9rnsr: Do you know about https://issues.dlang.org/show_bug.cgi?id=12410 ?

[monarchdodra]

Review? This is pretty trivial...

[Orvid]

Shouldn't these attributes already be getting inferred? If not, does this need to be marked with a bug number?

[JakobOvrum]

No, it is not within a template, neither directly or indirectly.

[Orvid]

Ah, woops, must have misread a changelog at some point. I just never noticed because I always mark mine explicitly anyways.

[JakobOvrum]

LGTM. Maybe the error handling code could be ported to nothrow quite neatly by using assumeWontThrow where appropriate.

[monarchdodra]

Maybe the error handling code could be ported to nothrow quite neatly by using assumeWontThrow where appropriate.

Maybe. But even then, we'd also need to tag on assumePure, assumeSafe and assume NOGC too. Not impossible, but it is a lot of code overhead for what is just a diagnostic.

or, we could extend asserts to not be considered for inference?

[ghost]

Auto-merge toggled on

[bearophile]

Perhaps I am doing something wrong, but this code doesn't compile to me, giving a "Error: 'std.algorithm.sort!("a < b", cast(SwapStrategy)0, int[]).sort' is not nothrow":

void main() nothrow {
    import std.algorithm;
    auto data = [5, 3,  2, 1];
    sort(data);
}

[monarchdodra]

Perhaps I am doing something wrong, ...

Are you correctly rebased? It's working for me.

[bearophile]

Are you correctly rebased? It's working for me.

I have updated all the dmd/Phobos/druntime files with GIT, but I still see the nothrow problem. I don't know why.

[ghost]

Please rebase again, it works fine locally with commits:

DMD: dlang/dmd@c5ebee1
Druntime: dlang/druntime@6a49753
Phobos: c61c123

[bearophile]

Now it compiles and I have found the cause of my error, I was compiling using the "-debug" switch.

[ghost]

Hmm if it fails with -debug then I think that's an oversight. @monarchdodra?

[monarchdodra]

Hmm if it fails with -debug then I think that's an oversight. @monarchdodra?

I'll look into it. I'd argue the root issue though is that anything in debug should be marked nothrow, and silently caught, to concede for useability. It's already pure...

https://issues.dlang.org/show_bug.cgi?id=8464
https://issues.dlang.org/show_bug.cgi?id=10854

But in the meantime, yeah, there's an issue somewhere I'll look into.

[ghost]

@monarchdodra: Just filed https://issues.dlang.org/show_bug.cgi?id=12657

[monarchdodra]

there's an issue somewhere I'll look into.

#2154.