Add implementation of Extend for () #50234

cramertj · 2018-04-25T22:07:04Z

This is useful in some generic code which wants to collect iterators of items into a result.

rust-highfive · 2018-04-25T22:07:07Z

r? @Kimundi

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pietroalbini · 2018-04-30T11:31:53Z

Ping from triage @Kimundi! This PR needs your review.

Kimundi · 2018-04-30T11:47:27Z

@rfcbot fcp merge

kennytm · 2018-05-01T20:09:27Z

@rust-lang/libs Please summon rfcbot again, thanks.

alexcrichton · 2018-05-01T21:05:40Z

@rfcbot fcp merge

rfcbot · 2018-05-01T21:05:40Z

Team member @alexcrichton has proposed to merge this. The next step is review by the rest of the tagged teams:

No concerns currently listed.

Once a majority of reviewers approve (and none object), 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.

withoutboats · 2018-05-02T07:40:39Z

This is useful in some generic code which wants to collect iterators of items into a result.

Could you show an example?

cramertj · 2018-05-02T17:03:49Z

@withoutboats The specific case where I hit this was wanting to StreamExt::collect a stream into () so that all the elements will be evaluated and an error will be returned if any of them failed.

sfackler · 2018-05-02T17:32:49Z

src/libcore/iter/traits.rs

+#[stable(feature = "extend_for_unit", since = "1.27.0")]
+impl Extend<()> for () {
+    fn extend<T: IntoIterator<Item = ()>>(&mut self, iter: T) {
+        for _ in iter {}


I believe iter.for_each(drop) can be faster for some iterators like chain.

Huh, interesting.

rfcbot · 2018-05-04T04:23:39Z

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

kennytm · 2018-05-08T21:13:22Z

src/libcore/iter/traits.rs

@@ -352,6 +352,13 @@ pub trait Extend<A> {
    fn extend<T: IntoIterator<Item=A>>(&mut self, iter: T);
 }

+#[stable(feature = "extend_for_unit", since = "1.27.0")]


This should become 1.28.0.

rfcbot · 2018-05-14T04:45:33Z

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

alexcrichton · 2018-05-14T13:51:12Z

@bors: r+

bors · 2018-05-14T13:51:14Z

📌 Commit 5028b9c has been approved by alexcrichton

alexcrichton · 2018-05-14T13:51:21Z

@bors: r-

er oops, mind updating the stability attribute?

alexcrichton · 2018-05-14T13:51:38Z

Also while you're at it, mind adding a small test?

kennytm · 2018-05-20T07:03:27Z

@bors r=alexcrichton rollup

bors · 2018-05-20T07:03:28Z

📌 Commit a74e168 has been approved by alexcrichton

bors · 2018-05-20T20:29:17Z

⌛ Testing commit a74e168 with merge a1d4a95...

Add implementation of Extend for () This is useful in some generic code which wants to collect iterators of items into a result.

bors · 2018-05-20T22:37:01Z

☀️ Test successful - status-appveyor, status-travis
Approved by: alexcrichton
Pushing a1d4a95 to master...

Mirrors rust-lang/rust#50234

683: impl ParallelExtend<()> for () r=cuviper a=cuviper Mirrors rust-lang/rust#50234 Co-authored-by: Josh Stone <cuviper@gmail.com>

rust-highfive assigned Kimundi Apr 25, 2018

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cramertj force-pushed the extend branch from d039bfe to cf475cc Compare April 25, 2018 22:26

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cramertj force-pushed the extend branch from cf475cc to d736ca7 Compare April 25, 2018 22:37

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cramertj force-pushed the extend branch from d736ca7 to 3a0a67f Compare May 2, 2018 17:46

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cramertj force-pushed the extend branch from 3a0a67f to 5028b9c Compare May 2, 2018 17:55

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels May 4, 2018

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cramertj force-pushed the extend branch from 5028b9c to 3851a87 Compare May 14, 2018 18:38

Add implementation of Extend for ()

a74e168

cramertj force-pushed the extend branch from 3851a87 to a74e168 Compare May 14, 2018 18:50

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bors added a commit that referenced this pull request May 20, 2018

Auto merge of #50234 - cramertj:extend, r=alexcrichton

a1d4a95

Add implementation of Extend for () This is useful in some generic code which wants to collect iterators of items into a result.

bors merged commit a74e168 into rust-lang:master May 20, 2018

cramertj deleted the extend branch May 21, 2018 20:02

cuviper added a commit to cuviper/rayon that referenced this pull request Aug 15, 2019

impl ParallelExtend<()> for ()

c6a294b

Mirrors rust-lang/rust#50234

cuviper mentioned this pull request Aug 15, 2019

impl ParallelExtend<()> for () rayon-rs/rayon#683

Merged

bors bot added a commit to rayon-rs/rayon that referenced this pull request Aug 22, 2019

Merge #683

d993d7a

683: impl ParallelExtend<()> for () r=cuviper a=cuviper Mirrors rust-lang/rust#50234 Co-authored-by: Josh Stone <cuviper@gmail.com>

ibraheemdev mentioned this pull request Feb 19, 2022

Enable draining iterator/stream elements into a () #94166

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Add implementation of Extend for () #50234

Add implementation of Extend for () #50234

cramertj commented Apr 25, 2018

rust-highfive commented Apr 25, 2018

pietroalbini commented Apr 30, 2018

Kimundi commented Apr 30, 2018

kennytm commented May 1, 2018

alexcrichton commented May 1, 2018

rfcbot commented May 1, 2018 •

edited by dtolnay

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withoutboats commented May 2, 2018

cramertj commented May 2, 2018

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bors commented May 20, 2018

Add implementation of Extend for () #50234

Add implementation of Extend for () #50234

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cramertj commented Apr 25, 2018

rust-highfive commented Apr 25, 2018

pietroalbini commented Apr 30, 2018

Kimundi commented Apr 30, 2018

kennytm commented May 1, 2018

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rfcbot commented May 1, 2018 •

edited by dtolnay

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