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Merged
merged 3 commits into from
Nov 27, 2025
Merged

constify from_fn, try_from_fn, try_map, map #147071

merged 3 commits into from
Nov 27, 2025
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@bend-n bend-n commented Sep 26, 2025 •
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adds the const_array feature
reimplements try_map in more or less the same way

@rustbot rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Sep 26, 2025
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@bend-n bend-n marked this pull request as ready for review September 26, 2025 18:44
@rustbot rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 26, 2025
@rustbot rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Sep 26, 2025
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r? @ibraheemdev

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oli-obk
oli-obk requested changes Oct 11, 2025
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library/core/src/array/mod.rs Outdated
else {
// SAFETY: this slice will contain only initialized objects.
unsafe {
x.array_mut.get_unchecked_mut(..x.initialized).assume_init_drop();
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What part of this isn't const evaluable? The get_unchecked_mut?

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@bend-n bend-n Oct 11, 2025 •
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assume_init_drop, and changing it to be const had some rammifications for some reason, causing some tests to fail. #147071 (comment)

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Looks like just trivial stderr file changes. Feel free to just bless them.

But is that code path testable in const? Since it's only happening in a panic path, I think it's unreachable anyway in const contexts. They never unwind and never will unwind. So maybe just document that and move the entire drop method body into the non-const code path... Or can we keep it non-const and avoid any drop happening for it by "disarming it" in the success path?

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its used in try_from_fn, so it can get dropped in const context?

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Ah right. Hmm. Wondering how to write an observable test for this. I think if you use a type with a reference to a Cell and in its const drop impl increment that cell, you should see in a const context that the cell isn't incremented if try_map errors/returns None.

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Ah oops, wanted to write this test but forgot about it when I was on a computer.

Need to reinvestigate this to get it all back into cache.

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It oughtnt really be needed now, as the behaviour is identical to the non const version?

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@oli-obk oli-obk assigned oli-obk and unassigned ibraheemdev Oct 11, 2025
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rustbot commented Oct 11, 2025

The Miri subtree was changed

cc @rust-lang/miri

@bend-n bend-n force-pushed the const_array-ops branch 3 times, most recently from e95a529 to 0021344 Compare October 11, 2025 11:43
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@bend-n bend-n force-pushed the const_array-ops branch 2 times, most recently from 43edafa to 7bec7a4 Compare October 11, 2025 12:03
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bend-n
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library/core/src/array/drain.rs Outdated
where
F: [const] FnMut(T) -> U,
{
extern "rust-call" fn call_mut(&mut self, (i,): (usize,)) -> Self::Output {
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@bend-n bend-n Oct 11, 2025 •
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it would be possible to ignore this i and just use moved, but, uh, i think that would be somewhat confusing.

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rustbot commented Nov 26, 2025

Some changes occurred in src/tools/cargo

cc @ehuss

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@bend-n bend-n requested a review from oli-obk November 27, 2025 04:28
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just a rebase fragemtn and a nit

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rustbot commented Nov 27, 2025

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

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oli-obk commented Nov 27, 2025

@bors r+

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bors commented Nov 27, 2025

📌 Commit e3a2c23 has been approved by oli-obk

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 27, 2025
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bors added a commit that referenced this pull request Nov 27, 2025
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Auto merge of #149397 - matthiaskrgr:rollup-go79y6a, r=matthiaskrgr
c86564c 
Rollup of 8 pull requests

Successful merges:

 - #147071 (constify from_fn, try_from_fn, try_map, map)
 - #148930 (tweak editor configs)
 - #149320 (-Znext-solver: normalize expected function input types when fudging)
 - #149363 (Port the `#![windows_subsystem]` attribute to the new attribute system)
 - #149378 (make run-make tests use 2024 edition by default)
 - #149381 (Add `impl TrustedLen` on `BTree{Map,Set}` iterators)
 - #149388 (remove session+blob decoder construction)
 - #149390 (`rust-analyzer` subtree update)

r? `@ghost`
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@bors bors merged commit b1b3e5e into rust-lang:main Nov 27, 2025
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@rustbot rustbot added this to the 1.93.0 milestone Nov 27, 2025
rust-timer added a commit that referenced this pull request Nov 27, 2025
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Unrolled build for #147071
e8a904b 
Rollup merge of #147071 - bend-n:const_array-ops, r=oli-obk

constify from_fn, try_from_fn, try_map, map

adds the `const_array` feature
reimplements `try_map` in more or less the same way
@bend-n bend-n deleted the const_array-ops branch November 28, 2025 04:34
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