eefriedman commented on Aug 13, 2015

Note that the fixed_size_array feature specifically covers the FixedSizeArray trait. There's some other code in core::array, but it's all implicitly stable.

bluss commented on Aug 13, 2015

The FixedSizeArray trait would be great, except for many uses the ranges of sizes it's implemented for simply isn't what you need, and there is no way to expand it. Thus it is mostly useless in the current form.

SimonSapin commented on Aug 13, 2015

Could the compiler magically have an "infinite" (generated on demand) number of impls of FixedSizeArray?

If that happens and the type parameter is made into an associated type (and maybe an associated const for the size is added), then most of the other impls that currently only go up to N=32 could be made generic impl<A: FixedSizeArray> … for A.

bluss commented on Aug 13, 2015

If/when the issue of using associated consts like consts is resolved, that is, allow [i32; A::LEN] to compile; then an infinite number of FixedSizeArray impls would give us the same thing as generic integer parameters.

This suggests to me that completing associated constants is basically the same problem as allowing generic integer parameters.

oli-obk commented on Aug 13, 2015

for now FixedSizeArray could be moved to a crate since it doesn't use any compiler magic anyway

Triage: no changes

SimonSapin commented on Feb 21, 2017

Something did change in #28088: this trait is now implemented for all sizes:

unsafe impl<T, A: Unsize<[T]>> FixedSizeArray<T> for A

The Unsize trait is also unstable: #27732

SimonSapin commented on Feb 21, 2017

I wrote rust-lang/rfcs#1915 about extending and stabilizing this trait.

Amanieu commented 11 days ago

This trait isn't used anywhere and doesn't seem to be needed any more now that we have const generics.

@rfcbot fcp close

rfcbot commented 11 days ago •

Team member @Amanieu has proposed to close this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

rfcbot commented 10 days ago

This is now entering its final comment period, as per the review above.

rfcbot commented 5 hours ago

The final comment period, with a disposition to close, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.