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Deref patterns #88

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nikomatsakis opened this issue Mar 9, 2021 · 9 comments
Open

Deref patterns #88

nikomatsakis opened this issue Mar 9, 2021 · 9 comments
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@cramertj
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lang-initiative An active lang team initiative T-lang
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@nikomatsakis
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nikomatsakis commented Mar 9, 2021 •
edited by cramertj
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Summary

  • Allow pattern matching through types that impl Deref or DerefMut.
  • Limited to types in stdlib where we can manually annotate them as pure for now.

Info

What is this issue?

This issue represents an active project group. It is meant to be used for
the group to post updates to the lang team (and others) in a lightweight
fashion. Please do not use the comments here for discussion, that should be kept
in the Zulip stream (discussion comments here will be marked as off-topic).
@nikomatsakis nikomatsakis added lang-initiative An active lang team initiative T-lang labels Mar 9, 2021
@nikomatsakis nikomatsakis added this to Active Projects (Design) in Lang Team Mar 9, 2021
@nikomatsakis nikomatsakis mentioned this issue Mar 9, 2021
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@chorman0773
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Update on Current Status:

  • The most recent topic of discussion has been on the stdlib types list, with no current resolution. Syntax discussions have not begun as of yet.
  • Syntax Discussions could possibly benefit from a design meeting, though I'd probably want to start the discussion on the zulip stream first.
  • Currently no concerns that I can see.

@estebank
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The discussion at https://internals.rust-lang.org/t/pre-pre-rfc-match-ergonomics-for-container-types-restricted-method-calls-in-patterns/13371 was fairly extensive as well.

@nikomatsakis
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@chorman0773

Notes from the planning meeting today:

  • Sounds great!
  • It would be nice to see the list of stdlib types, and if there are open questions about certain types, to describe those.

@chorman0773
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Update:

  • Limited Progress has been made since last update. The syntax discussion has been opened, but has seen limited progress.. It may be good for that to move to a design meeting.
  • The list of stdlib types last brought for consideration was Box, Arc, Rc, Vec, and String (as well as Pin<P> where P is one of the previous).

@chorman0773
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Progress Updates:

  • Currently limited progress has been made. Syntax and stdlib types discussion are open in the same place as last update.

@chorman0773
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Progress Update:

  • Since the last update, implementation work has begun (though limited progress has been made on that). It will initially use the "no syntax" option, and the work with the types presented above. A tracking issue has also been opened, Tracking issue: deref patterns rust#87121.

@cramertj cramertj self-assigned this Dec 16, 2021
@fee1-dead fee1-dead mentioned this issue Jul 5, 2022
Merged
@safinaskar
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For those who cannot wait: my proc macro crate with deref patterns: https://crates.io/crates/match_deref

Manishearth added a commit to Manishearth/rust that referenced this issue Nov 16, 2022
@Manishearth
Rollup merge of rust-lang#98914 - fee1-dead-contrib:min-deref-pattern…
9539eef 
…s, r=compiler-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 rust-lang#87121

~~I forgot to add a feature gate, will do so in a minute~~ Done
bors added a commit to rust-lang-ci/rust that referenced this issue Nov 20, 2022
@bors
Auto merge of rust-lang#98914 - fee1-dead-contrib:min-deref-patterns,…
e07425d 
… r=compiler-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 rust-lang#87121

~~I forgot to add a feature gate, will do so in a minute~~ Done
flip1995 pushed a commit to flip1995/rust-clippy that referenced this issue Nov 21, 2022
@bors
Auto merge of #98914 - fee1-dead-contrib:min-deref-patterns, r=compil…
80a4699 
…er-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 #87121

~~I forgot to add a feature gate, will do so in a minute~~ Done
RalfJung pushed a commit to RalfJung/miri that referenced this issue Nov 27, 2022
@bors
Auto merge of #98914 - fee1-dead-contrib:min-deref-patterns, r=compil…
6886ade 
…er-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 #87121

~~I forgot to add a feature gate, will do so in a minute~~ Done
thomcc pushed a commit to tcdi/postgrestd that referenced this issue Feb 10, 2023
@bors
Auto merge of #98914 - fee1-dead-contrib:min-deref-patterns, r=compil…
b658e77 
…er-errors

Minimal implementation of implicit deref patterns for Strings

cc `@compiler-errors` `@BoxyUwU` rust-lang/lang-team#88 #87121

~~I forgot to add a feature gate, will do so in a minute~~ Done
This was referenced Mar 3, 2024
Open
Merged
@Nadrieril
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I'm restarting work on this feature. I understand @cramertj isn't on T-lang anymore; would someone on T-lang be willing to take over the liaison role?

@ehuss ehuss mentioned this issue Mar 16, 2024
Merged
@Nadrieril
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@traviscross is taking over the liaison role!

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Mar 21, 2024
@matthiaskrgr
Rollup merge of rust-lang#122222 - Nadrieril:deref-pat-feature-gate, …
e1fb245 
…r=compiler-errors

deref patterns: bare-bones feature gate and typechecking

I am restarting the deref patterns experimentation. This introduces a feature gate under the lang-team [experimental feature](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md) process, with [`@cramertj` as lang-team liaison](rust-lang/lang-team#88) (it's been a while though, you still ok with this `@cramertj?).` Tracking issue: rust-lang#87121.

This is the barest-bones implementation I could think of:
- explicit syntax, reusing `box <pat>` because that saves me a ton of work;
- use `Deref` as a marker trait (instead of a yet-to-design `DerefPure`);
- no support for mutable patterns with `DerefMut` for now;
- MIR lowering will come in the next PR. It's the trickiest part.

My goal is to let us figure out the MIR lowering part, which might take some work. And hopefully get something working for std types soon.

This is in large part salvaged from `@fee1-dead's` rust-lang#119467.

r? `@compiler-errors`
workingjubilee added a commit to workingjubilee/rustc that referenced this issue Mar 21, 2024
@workingjubilee
Rollup merge of rust-lang#122222 - Nadrieril:deref-pat-feature-gate, …
d32819a 
…r=compiler-errors

deref patterns: bare-bones feature gate and typechecking

I am restarting the deref patterns experimentation. This introduces a feature gate under the lang-team [experimental feature](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md) process, with [``@cramertj`` as lang-team liaison](rust-lang/lang-team#88) (it's been a while though, you still ok with this ``@cramertj?).`` Tracking issue: rust-lang#87121.

This is the barest-bones implementation I could think of:
- explicit syntax, reusing `box <pat>` because that saves me a ton of work;
- use `Deref` as a marker trait (instead of a yet-to-design `DerefPure`);
- no support for mutable patterns with `DerefMut` for now;
- MIR lowering will come in the next PR. It's the trickiest part.

My goal is to let us figure out the MIR lowering part, which might take some work. And hopefully get something working for std types soon.

This is in large part salvaged from ``@fee1-dead's`` rust-lang#119467.

r? ``@compiler-errors``
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Mar 21, 2024
@matthiaskrgr
Rollup merge of rust-lang#122222 - Nadrieril:deref-pat-feature-gate, …
1eeeaa4 
…r=compiler-errors

deref patterns: bare-bones feature gate and typechecking

I am restarting the deref patterns experimentation. This introduces a feature gate under the lang-team [experimental feature](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md) process, with [```@cramertj``` as lang-team liaison](rust-lang/lang-team#88) (it's been a while though, you still ok with this ```@cramertj?).``` Tracking issue: rust-lang#87121.

This is the barest-bones implementation I could think of:
- explicit syntax, reusing `box <pat>` because that saves me a ton of work;
- use `Deref` as a marker trait (instead of a yet-to-design `DerefPure`);
- no support for mutable patterns with `DerefMut` for now;
- MIR lowering will come in the next PR. It's the trickiest part.

My goal is to let us figure out the MIR lowering part, which might take some work. And hopefully get something working for std types soon.

This is in large part salvaged from ```@fee1-dead's``` rust-lang#119467.

r? ```@compiler-errors```
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Mar 21, 2024
@matthiaskrgr
Rollup merge of rust-lang#122222 - Nadrieril:deref-pat-feature-gate, …
0867025 
…r=compiler-errors

deref patterns: bare-bones feature gate and typechecking

I am restarting the deref patterns experimentation. This introduces a feature gate under the lang-team [experimental feature](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md) process, with [````@cramertj```` as lang-team liaison](rust-lang/lang-team#88) (it's been a while though, you still ok with this ````@cramertj?).```` Tracking issue: rust-lang#87121.

This is the barest-bones implementation I could think of:
- explicit syntax, reusing `box <pat>` because that saves me a ton of work;
- use `Deref` as a marker trait (instead of a yet-to-design `DerefPure`);
- no support for mutable patterns with `DerefMut` for now;
- MIR lowering will come in the next PR. It's the trickiest part.

My goal is to let us figure out the MIR lowering part, which might take some work. And hopefully get something working for std types soon.

This is in large part salvaged from ````@fee1-dead's```` rust-lang#119467.

r? ````@compiler-errors````
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Mar 21, 2024
@rust-timer
Unrolled build for rust-lang#122222
dd55184 
Rollup merge of rust-lang#122222 - Nadrieril:deref-pat-feature-gate, r=compiler-errors

deref patterns: bare-bones feature gate and typechecking

I am restarting the deref patterns experimentation. This introduces a feature gate under the lang-team [experimental feature](https://github.com/rust-lang/lang-team/blob/master/src/how_to/experiment.md) process, with [````@cramertj```` as lang-team liaison](rust-lang/lang-team#88) (it's been a while though, you still ok with this ````@cramertj?).```` Tracking issue: rust-lang#87121.

This is the barest-bones implementation I could think of:
- explicit syntax, reusing `box <pat>` because that saves me a ton of work;
- use `Deref` as a marker trait (instead of a yet-to-design `DerefPure`);
- no support for mutable patterns with `DerefMut` for now;
- MIR lowering will come in the next PR. It's the trickiest part.

My goal is to let us figure out the MIR lowering part, which might take some work. And hopefully get something working for std types soon.

This is in large part salvaged from ````@fee1-dead's```` rust-lang#119467.

r? ````@compiler-errors````
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@nikomatsakis @safinaskar @estebank @chorman0773 @cramertj @Nadrieril