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Tracking issue for dyn upcasting coercion #65991

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19 of 21 tasks
Tracked by #165
, #131
...
alexreg opened this issue Oct 31, 2019 · 84 comments · Fixed by #118133
Open
19 of 21 tasks
Tracked by #165
, #131
...

Tracking issue for dyn upcasting coercion #65991

alexreg opened this issue Oct 31, 2019 · 84 comments · Fixed by #118133
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@crlf0710
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A-traits Area: Trait system C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. F-trait_upcasting `#![feature(trait_upcasting)]` finished-final-comment-period The final comment period is finished for this PR / Issue. S-tracking-design-concerns Status: There are blocking ❌ design concerns. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-lang Relevant to the language team, which will review and decide on the PR/issue. T-types Relevant to the types team, which will review and decide on the PR/issue.

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@alexreg
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alexreg commented Oct 31, 2019 •
edited by crlf0710
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This is a tracking issue for RFC3324. Corresponding MCP is here.
The feature gate for the issue is #![feature(trait_upcasting)].

STATUS UPDATE

We are in the process of stabilizing.

About tracking issues

Tracking issues are used to record the overall progress of implementation.
They are also used as hubs connecting to other relevant issues, e.g., bugs or open design questions.
A tracking issue is however not meant for large scale discussion, questions, or bug reports about a feature.
Instead, open a dedicated issue for the specific matter and add the relevant feature gate label.

Steps

Previous discussions

Unresolved Questions

  • Currently CoerceUnsized trait cannot express this case: a smart pointers that wrap a raw pointer and don't guarantee via a custom invariant that it is valid. Maybe a separate CoerceUnsizedUnsafe trait is needed. (see Trait upcasting coercion (part4) #88010 (comment)).
  • Should we make upcasting opt-in in some form to limit vtable size by default? The current inclination of the lang-team is "no", but it would be useful to gather data on how much supporting upcasting contributors to overall binary size.
  • Before stabilizing it we should check that libs-api is ok with upcasting for all dyn-allowed traits in the library, since those we can't change. (addressed by Tracking issue for dyn upcasting coercion #65991 (comment))
  • Should we add an opt-out mechanism, and extend library stabilization checklist with "do we want to opt-out for now"?

Implementation history
@alexreg alexreg added the C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. label Oct 31, 2019
@Centril Centril added the T-lang Relevant to the language team, which will review and decide on the PR/issue. label Oct 31, 2019
@Centril Centril added the F-trait_upcasting `#![feature(trait_upcasting)]` label Oct 31, 2019
@alexreg alexreg added A-traits Area: Trait system T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Oct 31, 2019
This was referenced Jun 14, 2021
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bors added a commit to rust-lang-ci/rust that referenced this issue Jun 16, 2021
@bors
Auto merge of rust-lang#86291 - crlf0710:trait_vtbl_refactor, r=bjorn3
2336406 
Refactor vtable codegen

This refactor the codegen of vtables of miri interpreter, llvm, cranelift codegen backends.

This is preparation for the implementation of trait upcasting feature. cc rust-lang#65991

Note that aside from code reorganization, there's an internal behavior change here that now InstanceDef::Virtual's index now include the three metadata slots, and now the first method is with index 3.

cc  `@RalfJung` `@bjorn3`
bjorn3 pushed a commit to bjorn3/rust that referenced this issue Jul 7, 2021
@bors
Auto merge of rust-lang#86291 - crlf0710:trait_vtbl_refactor, r=bjorn3
9be7ca0 
Refactor vtable codegen

This refactor the codegen of vtables of miri interpreter, llvm, cranelift codegen backends.

This is preparation for the implementation of trait upcasting feature. cc rust-lang#65991

Note that aside from code reorganization, there's an internal behavior change here that now InstanceDef::Virtual's index now include the three metadata slots, and now the first method is with index 3.

cc  `@RalfJung` `@bjorn3`
@crlf0710 crlf0710 changed the title Tracking issue for trait upcasting Tracking issue for trait upcasting coercion Jul 8, 2021
@avanhatt avanhatt mentioned this issue Jul 26, 2021
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This was referenced Aug 16, 2021
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@vks vks mentioned this issue Sep 20, 2021
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@ilslv ilslv mentioned this issue Sep 22, 2021
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@Tamschi Tamschi mentioned this issue Sep 22, 2021
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@Jesterhearts Jesterhearts mentioned this issue Dec 11, 2021
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@nikomatsakis
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This is currently blocked on resolving the safety conditions for upcasting. The following updated document describes my current thinking, looking for feedback:

https://rust-lang.github.io/dyn-upcasting-coercion-initiative/design-discussions/upcast-safety-2.html

@dimpolo
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dimpolo commented Feb 4, 2022

I was playing around with this and discovered that the feature gate (and its incomplete_features warning) can be bypassed using #![feature(unsize)] instead.

This will upcast a &dyn Bar where Foo is a supertrait of Bar.

fn upcast<Dyn: ?Sized + Unsize<dyn Foo>>(bar: &Dyn) -> &dyn Foo { bar }

Playground

Would this mean the unsize feature should be incomplete as well?

@dimpolo dimpolo mentioned this issue Feb 7, 2022
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@danielhenrymantilla
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danielhenrymantilla commented Feb 11, 2022 •
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Came to comment the same observation that @dimpolo has made: I think the impl of Unsize<dyn '_ + Super> for dyn '_ + Sub ought, itself, to be feature-gated by trait_upcasting.

@nikomatsakis
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That makes sense, although really I just want to stabilize this.

@joshtriplett joshtriplett added S-tracking-ready-to-stabilize Status: This is ready to stabilize; it may need a stabilization report and a PR S-waiting-on-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). labels Jun 22, 2022
@nkysg nkysg mentioned this issue Jul 22, 2022
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@Mark-Simulacrum
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cc #89460, which is tracking a future-compat lint that seems related to this feature.

@crlf0710 crlf0710 changed the title Tracking issue for trait upcasting coercion Tracking issue for dyn upcasting coercion Jul 28, 2022
@Urgau Urgau mentioned this issue Jan 15, 2024
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@steffahn
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I’ve come across some soundness issues with upcasting today. Readers of this thread might be interested ^^

@ehuss ehuss mentioned this issue Jan 22, 2024
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@oli-obk oli-obk reopened this Jan 22, 2024
@wesleywiser wesleywiser added S-tracking-design-concerns Status: There are blocking ❌ design concerns. and removed S-waiting-on-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). S-tracking-ready-to-stabilize Status: This is ready to stabilize; it may need a stabilization report and a PR labels Jan 25, 2024
@Wodann Wodann mentioned this issue Feb 5, 2024
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@Dirbaio Dirbaio mentioned this issue Feb 23, 2024
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ltratt added a commit to ltratt/yk that referenced this issue Mar 7, 2024
@ltratt
Add CompiledTrace::as_any to allow upcasting to Any.
2781908 
Unfortunately, trait upcasting is still
[incomplete/unstable](rust-lang/rust#65991).
Forcing every implementation of `CompiledTrace` to implement `as_any` is
a manual way of allow upcasting.

Counter-intuitively, we use the upcast to `Any` to allow us to downcast
to a concrete implementation of `CompiledTrace`. `depot.rs` can now call
`downcast::<LLVMCompiledTrace>` to get at the `LLVMCompiledTrace`.

This will then allow us to push methods out of `CompiledTrace` and into
`LLVMCompiledTrace`.
ltratt added a commit to ltratt/yk that referenced this issue Mar 7, 2024
@ltratt
Add CompiledTrace::as_any to allow upcasting to Any.
b49f042 
Unfortunately, trait upcasting is still
[incomplete/unstable](rust-lang/rust#65991).
Forcing every implementation of `CompiledTrace` to implement `as_any` is
a manual way of allow upcasting.

Counter-intuitively, we use the upcast to `Any` to allow us to downcast
to a concrete implementation of `CompiledTrace`. `depot.rs` can now call
`downcast::<LLVMCompiledTrace>` to get at the `LLVMCompiledTrace`.

This will then allow us to push methods out of `CompiledTrace` and into
`LLVMCompiledTrace`.
@PoignardAzur
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Can we have a status update with regards to the reverted stabilization? The current status update says "We are in the process of stabilizing" since January, with no mention of the recent soundness issues.

@WaffleLapkin
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The stabilization is currently blocked on the fix of the unsoundness bug tracked in #120222. The fix is in #120248, but needs a bit more work. I've been occupied by the never type stuff which is urgent because some of the changes are edition based. I hope I'll have time soon to finish #120248.

This is also blocked on rust reference PR, which someone needs to take over: rust-lang/reference#1259 (comment).

@jayzhan211 jayzhan211 mentioned this issue May 9, 2024
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@ROMemories ROMemories mentioned this issue May 22, 2024
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mark-beck added a commit to cep-sose2024/rust-crypto-netwatch that referenced this issue May 27, 2024
@mark-beck
fix: change traits to use Box<dyn Any>
9ceffcd 
When using Box<dyn ProviderConfig>, you would have to upcast the dyn ProviderConfig to dyn Any. This feature is currently experimental (rust-lang/rust#65991). As ProviderConfig is always going to be turned into an Any, it has no real purpose anyways.
BREAKING
@CertainLach CertainLach mentioned this issue May 27, 2024
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@mark-beck mark-beck mentioned this issue May 28, 2024
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ngussek pushed a commit to nmshd/rust-crypto that referenced this issue Jun 4, 2024
@mark-beck @markoisus @DexterHK
Adding Android Keystore Provider and Keyhandle by Team Netwatch (B) (#5)
e215f72 
* feat: added internal work to fork

* fix: added missing changes

* feat: implemented config

* fix: added lib cratetype

* fix: AndroidConfig has to be public

* fix: missing match in instance

* fix: don't load java vm in initialize_module, as it will be called before the config was passed

* feat: added default logging implementation for android

* feat: implemented symmetric algorithm for encryption, *not tested

* fix: change traits to use Box<dyn Any>

When using Box<dyn ProviderConfig>, you would have to upcast the dyn ProviderConfig to dyn Any. This feature is currently experimental (rust-lang/rust#65991). As ProviderConfig is always going to be turned into an Any, it has no real purpose anyways.
BREAKING

* test(mod.rs): adding the tests again

* feat: Add set_key_size and set_algorithm_parameter_spec methods to Builder

* fix: Update set_algorithm_parameter_spec method in Builder

* feat: docs for set_block_modes, set_key_size and set_algorithm_parameter_spec

* fix: builder methods using wrong parameters

* feat: wrapped KeyGenerator for symmetric encryption

* feat: added symetrical encryption for android

* fix: added more paddings

* fix: readded common tests

* fix: readded other tests

* fix: mod.rs

* fix: wrang hash names for signature

---------

Co-authored-by: markoisus <marko.nikolic34567@gmail.com>
Co-authored-by: Dexter <84778260+DexterHK@users.noreply.github.com>
Co-authored-by: Baibars <dexterhk01@gmail.com>
@imrn99 imrn99 mentioned this issue Jun 10, 2024
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@Kish29
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Kish29 commented Jul 16, 2024

It looks like the blocking bug #120222 have been fixed out, and what's next for this stabilization?

@WaffleLapkin
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@Kish29 the next steps are changing the reference (cc rust-lang/reference#1259) and doing a new stabilization PR :)

@theweipeng theweipeng mentioned this issue Aug 11, 2024
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@wtzhang23 wtzhang23 mentioned this issue Sep 12, 2024
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@kpreid kpreid mentioned this issue Sep 14, 2024
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Zalathar added a commit to Zalathar/rust that referenced this issue Sep 15, 2024
@Zalathar
Rollup merge of rust-lang#130370 - kpreid:patch-2, r=compiler-errors
2cef6d1 
unstable-book: `trait_upcasting` example should not have `#![allow(incomplete_features)]`

Tracking issue: rust-lang#65991

`trait_upcasting` is not currently an incomplete feature; therefore examples of its use do not require `#![allow(incomplete_features)]`.
Zalathar added a commit to Zalathar/rust that referenced this issue Sep 15, 2024
@Zalathar
Rollup merge of rust-lang#130370 - kpreid:patch-2, r=compiler-errors
4b6f838 
unstable-book: `trait_upcasting` example should not have `#![allow(incomplete_features)]`

Tracking issue: rust-lang#65991

`trait_upcasting` is not currently an incomplete feature; therefore examples of its use do not require `#![allow(incomplete_features)]`.
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Sep 15, 2024
@rust-timer
Unrolled build for rust-lang#130370
a7571a1 
Rollup merge of rust-lang#130370 - kpreid:patch-2, r=compiler-errors

unstable-book: `trait_upcasting` example should not have `#![allow(incomplete_features)]`

Tracking issue: rust-lang#65991

`trait_upcasting` is not currently an incomplete feature; therefore examples of its use do not require `#![allow(incomplete_features)]`.
@jgcodes2020 jgcodes2020 mentioned this issue Sep 21, 2024
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A-traits Area: Trait system C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. F-trait_upcasting `#![feature(trait_upcasting)]` finished-final-comment-period The final comment period is finished for this PR / Issue. S-tracking-design-concerns Status: There are blocking ❌ design concerns. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-lang Relevant to the language team, which will review and decide on the PR/issue. T-types Relevant to the types team, which will review and decide on the PR/issue.
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