Support for Safe Haskell about vector

[Shimuuar]

I propose to close this as wontfix for following reasons:

1. vector exports a lot of memory unsafe functions
2. History of bugs (#188, #257) shows that even safe functions aren't all that safe
3. Safe extension didn't get much traction

[dolio]

Yeah, I'm not wild about marking vector trustworthy.

I think what might be best is to separate out Unsafe modules, which contain unsafeFoo. Those are marked unsafe. Then the normal modules could export just the things that do bounds checking, and can be declared trustworthy.

I'm actually not a great fan of unsafeFoo vs. foo. But I guess I'll create a new ticket to talk about that issue.

[cartazio]

that's a great idea!
If the spec on safe haskell
on the wiki is up to date, i think Safe inferred might be impossible without someone actually putting in the time to do a nontrivial refactoring, though TrustWorthy might be possible

RULES: As they can change the behaviour of trusted code in unanticipated ways, violating semantic consistency they are restricted in function. Specifically any RULES defined in a module M compiled with -XSafe are dropped. RULES defined in trustworthy modules that M imports are still valid and will fire as usual.

[cartazio]

basically: i think the only option is marking things trusworthy, at least for the "safe" modules, because we need the rewrite rules to work

[Zemyla]

What about specific Data.Vector.???.Safe modules, marked as Trustworthy, that only reexport safe methods?

[cartazio]

it probably makes the most sense to just mark vector as trust worthy wholesale. Honestly no part of vector is truly safe unless you build with bounds checks enabled :)

[Shimuuar]

But since vector export unsafe* functions it's not exactly trustworthy.

[cartazio]

true :)
in some sense, the only way to make it trustworthy would be to add bounds checks to all the unsafe code, right?

[chessai]

I'm onboard with @Shimuuar here, for all the same reasons.

[cartazio]

Plus safe mode disables any form of rules based optimization.

…

On Sat, Feb 1, 2020 at 1:50 PM chessai ***@***.***> wrote: I'm onboard with @Shimuuar <https://github.com/Shimuuar> here, for all the same reasons. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#56?email_source=notifications&email_token=AAABBQVA5WFBD67IITEBBTTRAW76RA5CNFSM4AXOFBPKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEKRD7MY#issuecomment-581058483>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAABBQSTKHWH7YKB7DMWJ3TRAW76RANCNFSM4AXOFBPA> .

[chessai]

Closing. Anyone feel free to reopen if a new argument arises for needing this.