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Stabilize enum is_variant methods as const #76225

Closed
5 of 6 tasks
Tracked by #16
CDirkx opened this issue Sep 1, 2020 · 2 comments
Closed
5 of 6 tasks
Tracked by #16

Stabilize enum is_variant methods as const #76225

CDirkx opened this issue Sep 1, 2020 · 2 comments
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A-const-fn Area: const fn foo(..) {..}. Pure functions which can be applied at compile time. C-feature-request Category: A feature request, i.e: not implemented / a PR. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.

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@CDirkx
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CDirkx commented Sep 1, 2020 •
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Recently const control flow was stabilized, which enables a lot of methods within the standard library to be made stable const; specifically all of the enum is_variant methods:

  • Option: is_some and is_none
  • Result: is_ok and is_err
  • Poll: is_ready and is_pending
  • Cow: is_borrowed and is_owned (methods themselves are unstable)
  • IpAddr: is_ipv4 and is_ipv6
  • std::path::Prefix: is_verbatim

This issue aims to collect discussion about the stabilization of these methods, due to their similarities and trivial implementations.

Stabilization

  • Option: stabilized in PR#76135 (note: also contains as_ref)
  • Result: stabilized in PR#76136 (note: also contains as_ref)
  • Poll stabilized in PR#76227
  • Cow: methods made const in PR#76139, the methods themselves are still unstable under cow_is_borrowed
  • IpAddr: stabilized in PR#76226
  • Prefix: stabilization proposed in PR#76232, but there is not enough motivation to stabilize this method on its own
@jonas-schievink jonas-schievink added A-const-fn Area: const fn foo(..) {..}. Pure functions which can be applied at compile time. C-feature-request Category: A feature request, i.e: not implemented / a PR. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Sep 1, 2020
This was referenced Sep 1, 2020
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@CDirkx
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CDirkx commented Sep 2, 2020

These were all the instances of enums with is_variant methods I could find in the standard library.

PRs opened for all of them, @ecstatic-morse

RalfJung added a commit to RalfJung/rust that referenced this issue Sep 19, 2020
@RalfJung
Rollup merge of rust-lang#76135 - CDirkx:const-option, r=dtolnay
af0594f 
Stabilize some Option methods as const

Stabilize the following methods of `Option` as const:
 - `is_some`
 - `is_none`
 - `as_ref`

These methods are currently const under the unstable feature `const_option` (tracking issue: rust-lang#67441).
I believe these methods to be eligible for stabilization because of the stabilization of rust-lang#49146 (Allow if and match in constants) and the trivial implementations, see also:  [PR#75463](rust-lang#75463).

Related: rust-lang#76225
bors added a commit to rust-lang-ci/rust that referenced this issue Sep 20, 2020
@bors
Auto merge of rust-lang#76136 - CDirkx:const-result, r=dtolnay
b873fa6 
Stabilize some Result methods as const

Stabilize the following methods of Result as const:
 - `is_ok`
 - `is_err`
 - `as_ref`

A test is also included, analogous to the test for `const_option`.

These methods are currently const under the unstable feature `const_result` (tracking issue: rust-lang#67520).
I believe these methods to be eligible for stabilization because of the stabilization of rust-lang#49146 (Allow if and match in constants) and the trivial implementations, see also: [PR#75463](rust-lang#75463) and [PR#76135](rust-lang#76135).

Note: these methods are the only methods currently under the `const_result` feature, thus this PR results in the removal of the feature.

Related: rust-lang#76225
RalfJung added a commit to RalfJung/rust that referenced this issue Sep 21, 2020
@RalfJung
Rollup merge of rust-lang#76135 - CDirkx:const-option, r=dtolnay,oli-obk
c3abb82 
Stabilize some Option methods as const

Stabilize the following methods of `Option` as const:
 - `is_some`
 - `is_none`
 - `as_ref`

These methods are currently const under the unstable feature `const_option` (tracking issue: rust-lang#67441).
I believe these methods to be eligible for stabilization because of the stabilization of rust-lang#49146 (Allow if and match in constants) and the trivial implementations, see also:  [PR#75463](rust-lang#75463).

Related: rust-lang#76225
flip1995 pushed a commit to flip1995/rust that referenced this issue Sep 24, 2020
@bors
Auto merge of rust-lang#76136 - CDirkx:const-result, r=dtolnay
a334ae6 
Stabilize some Result methods as const

Stabilize the following methods of Result as const:
 - `is_ok`
 - `is_err`
 - `as_ref`

A test is also included, analogous to the test for `const_option`.

These methods are currently const under the unstable feature `const_result` (tracking issue: rust-lang#67520).
I believe these methods to be eligible for stabilization because of the stabilization of rust-lang#49146 (Allow if and match in constants) and the trivial implementations, see also: [PR#75463](rust-lang#75463) and [PR#76135](rust-lang#76135).

Note: these methods are the only methods currently under the `const_result` feature, thus this PR results in the removal of the feature.

Related: rust-lang#76225
m-ou-se added a commit to m-ou-se/rust that referenced this issue Nov 7, 2020
@m-ou-se
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
e8c698b 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
m-ou-se added a commit to m-ou-se/rust that referenced this issue Nov 7, 2020
@m-ou-se
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
1b9f58d 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
m-ou-se added a commit to m-ou-se/rust that referenced this issue Nov 7, 2020
@m-ou-se
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
7b2754e 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
m-ou-se added a commit to m-ou-se/rust that referenced this issue Nov 7, 2020
@m-ou-se
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
4d486c9 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this issue Nov 8, 2020
@Dylan-DPC
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
e22a27f 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
m-ou-se added a commit to m-ou-se/rust that referenced this issue Nov 8, 2020
@m-ou-se
Rollup merge of rust-lang#76227 - CDirkx:const-poll, r=KodrAus
bdeace9 
Stabilize `Poll::is_ready` and `is_pending` as const

Insta-stabilize the methods `is_ready` and `is_pending` of `std::task::Poll` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225.
bors added a commit to rust-lang-ci/rust that referenced this issue Nov 23, 2020
@bors
Auto merge of rust-lang#76226 - CDirkx:const-ipaddr, r=dtolnay
1823a87 
Stabilize `IpAddr::is_ipv4` and `is_ipv6` as const

Insta-stabilize the methods `is_ipv4` and `is_ipv6` of `std::net::IpAddr` as const, in the same way as [PR#76198](rust-lang#76198).

Possible because of the recent stabilization of const control flow.

Part of rust-lang#76225 and rust-lang#76205.
@CDirkx
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CDirkx commented May 25, 2021

Closing as all is_variant methods have been stabilized as const, with the exception of Prefix which on its own doesn't seem worth it.

@CDirkx CDirkx closed this as completed May 25, 2021
@jplatte jplatte mentioned this issue May 31, 2021
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A-const-fn Area: const fn foo(..) {..}. Pure functions which can be applied at compile time. C-feature-request Category: A feature request, i.e: not implemented / a PR. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.
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