Skip to content

/rust

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

DST coercions #24619

Merged
merged 7 commits into from May 13, 2015

Conversation

Reviewers
No reviews
Assignees

@nikomatsakis nikomatsakis

Labels
None yet
Projects
None yet
Milestone
No milestone
7 participants
@nrc @brson @bombless @bors @bstrie @nikomatsakis @bluss
@nrc
Copy link
Member

nrc commented Apr 20, 2015

r? @nikomatsakis (note a few TODOs left in the code where I wasn't sure about stuff).

@rust-highfive rust-highfive assigned nikomatsakis Apr 20, 2015

@nrc nrc referenced this pull request Apr 20, 2015

Closed

[WIP] Implement DST coercions. #23785

@brson

This comment has been minimized.

Sign in to view
Copy link
Contributor

brson commented Apr 21, 2015

Should this be cherry-picked into 1.0?
@nrc

This comment has been minimized.

Sign in to view
Copy link
Member Author

nrc commented Apr 22, 2015

@brson I think no: it is a feature, not a fix, and it is large and thus potentially dangerous bug-wise. I think it is fine to wait an extra 6 weeks for.
@bombless

This comment has been minimized.

Sign in to view
Copy link
Contributor

bombless commented Apr 22, 2015

I think it is fine to wait an extra 6 weeks for.

Hmm, not 3 weeks from now?
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented Apr 22, 2015

☔️ The latest upstream changes (presumably #24674) made this pull request unmergeable. Please resolve the merge conflicts.
@bstrie

This comment has been minimized.

Sign in to view
Copy link
Contributor

bstrie commented Apr 23, 2015

This is awesome to see! I agree that it may be too late into the cycle to accept something this major into 1.0, but just for the heck of it do we know of any stdlib APIs that require unnecessarily-boxed trait objects that would benefit from this change?

P1start added a commit to P1start/rust that referenced this pull request Apr 23, 2015

@P1start
Make `UnsafeCell`, `RefCell`, `Mutex`, and `RwLock` accept DSTs 
This + DST coercions (rust-lang#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to
be simplified to `Rc<RefCell<Trait>>`.
17876ec

@P1start P1start referenced this pull request Apr 23, 2015

Merged

Make `UnsafeCell`, `RefCell`, `Mutex`, and `RwLock` accept DSTs #24737

@steveklabnik steveklabnik referenced this pull request Apr 30, 2015

Closed

ICE: Trait in an Rc #24984

bors added a commit that referenced this pull request May 1, 2015

@bors
Auto merge of #24737 - P1start:dst-cell, r=luqmana 
This + DST coercions (#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to be simplified to `Rc<RefCell<Trait>>`.
c22693d

P1start added a commit to P1start/rust that referenced this pull request May 1, 2015

@P1start
Make `UnsafeCell`, `RefCell`, `Mutex`, and `RwLock` accept DSTs 
This + DST coercions (rust-lang#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to
be simplified to `Rc<RefCell<Trait>>`.
aed293a
@nikomatsakis

This comment has been minimized.

Sign in to view
Copy link
Contributor

nikomatsakis commented May 1, 2015

@nrc sorry for the delay. I'm going to try and finish this review today. I've been wanting to dig specifically into the question of higher-ranked bounds and the use of skip-binder in this code, which doesn't seem right to me-- but I needed some time in quiet to think it through.

bors added a commit that referenced this pull request May 1, 2015

@bors
Auto merge of #24737 - P1start:dst-cell, r=luqmana 
This + DST coercions (#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to be simplified to `Rc<RefCell<Trait>>`.
4389a3b

P1start added a commit to P1start/rust that referenced this pull request May 2, 2015

@P1start
Make `UnsafeCell`, `RefCell`, `Mutex`, and `RwLock` accept DSTs 
This + DST coercions (rust-lang#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to
be simplified to `Rc<RefCell<Trait>>`.
57d8289

bors added a commit that referenced this pull request May 2, 2015

@bors
Auto merge of #24737 - P1start:dst-cell, r=alexcrichton 
This + DST coercions (#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to be simplified to `Rc<RefCell<Trait>>`.
c512850

bors added a commit that referenced this pull request May 3, 2015

@bors
Auto merge of #24737 - P1start:dst-cell, r=alexcrichton 
This + DST coercions (#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to be simplified to `Rc<RefCell<Trait>>`.
1fb4ecc

bors added a commit that referenced this pull request May 3, 2015

@bors
Auto merge of #24737 - P1start:dst-cell, r=alexcrichton 
This + DST coercions (#24619) would allow code like `Rc<RefCell<Box<Trait>>>` to be simplified to `Rc<RefCell<Trait>>`.
Loading status checks…
1a60dc4
@bluss

This comment has been minimized.

Sign in to view
Copy link
Contributor

bluss commented May 10, 2015

How does this impact stable APIs? Is there any way we can merge it and let mature and not insta-stabilize?

nrc added some commits Apr 14, 2015

@nrc
eddyb's changes for DST coercions 
+ lots of rebasing
843db01
@nrc
Make Rc DST-compatible
7d95353
@nrc
Fix a bunch of bugs 
* segfault due to not copying drop flag when coercing
* fat pointer casts
* segfault due to not checking drop flag properly
* debuginfo for DST smart pointers
* unreachable code in drop glue
03d4d5f
@nrc
Tests for custom coercions
db1b14a
@nrc
Rebasing
5d4cce6
@nrc
Fix binder skipping
Loading status checks…
31bb4ab

@nrc nrc force-pushed the nrc:rc-coerce branch from 89dd48c to 31bb4ab May 13, 2015

@nrc

This comment has been minimized.

Sign in to view
Copy link
Member Author

nrc commented May 13, 2015

@bors r=nikomatsakis 4446d44
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented May 13, 2015

⌛️ Testing commit 4446d44 with merge 17a4e3c...

bors added a commit that referenced this pull request May 13, 2015

@bors
Auto merge of #24619 - nrc:rc-coerce, r=nikomatsakis 
r? @nikomatsakis (note a few TODOs left in the code where I wasn't sure about stuff).
17a4e3c
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented May 13, 2015

💔 Test failed - auto-mac-64-opt
@nrc
Remove SNAP comments
Loading status checks…
b799cd8

@nrc nrc force-pushed the nrc:rc-coerce branch from 4446d44 to b799cd8 May 13, 2015

@nrc

This comment has been minimized.

Sign in to view
Copy link
Member Author

nrc commented May 13, 2015

@bors r=nikomatsakis b799cd8
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented May 13, 2015

⌛️ Testing commit b799cd8 with merge 32f3bff...

bors added a commit that referenced this pull request May 13, 2015

@bors
Auto merge of #24619 - nrc:rc-coerce, r=nikomatsakis 
r? @nikomatsakis (note a few TODOs left in the code where I wasn't sure about stuff).
32f3bff
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented May 13, 2015

⛄️ The build was interrupted to prioritize another pull request.
@bors

This comment has been minimized.

Sign in to view
Copy link
Contributor

bors commented May 13, 2015

⌛️ Testing commit b799cd8 with merge fa43387...

bors added a commit that referenced this pull request May 13, 2015

@bors
Auto merge of #24619 - nrc:rc-coerce, r=nikomatsakis 
r? @nikomatsakis (note a few TODOs left in the code where I wasn't sure about stuff).
Loading status checks…
fa43387
@bors

@bors bors merged commit b799cd8 into rust-lang:master May 13, 2015
2 checks passed

2 checks passed

continuous-integration/travis-ci/pr The Travis CI build passed
Details
homu Test successful
Details

This was referenced May 13, 2015

Closed
Closed
Merged
Merged

@huonw huonw referenced this pull request May 14, 2015

Closed

LLVM -O2 compile time regression #25393

This was referenced May 15, 2015

Merged
Closed

bors added a commit that referenced this pull request May 16, 2015

@bors
Auto merge of #25460 - P1start:rc-unsized-impls, r=luqmana 
Most of `Rc`’s trait implementations were DST-ified in #24619, but not these ones.
Loading status checks…
5e535ea

@nrc nrc referenced this pull request Jun 12, 2015

Merged

Update authors and relnotes for 1.1 #26200

This was referenced Mar 6, 2017

Closed
Merged

alexcrichton added a commit to alexcrichton/rust that referenced this pull request Mar 10, 2017

@alexcrichton
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
ddf1f20

alexcrichton added a commit to alexcrichton/rust that referenced this pull request Mar 10, 2017

@alexcrichton
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
3d781fd

arielb1 pushed a commit to arielb1/rust that referenced this pull request Mar 10, 2017

Ariel Ben-Yehuda
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
34261e2

arielb1 pushed a commit to arielb1/rust that referenced this pull request Mar 10, 2017

Ariel Ben-Yehuda
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
a6ef94b

arielb1 pushed a commit to arielb1/rust that referenced this pull request Mar 10, 2017

Ariel Ben-Yehuda
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
77da9de

alexcrichton added a commit to alexcrichton/rust that referenced this pull request Mar 10, 2017

@alexcrichton
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
74a8be4

arielb1 pushed a commit to arielb1/rust that referenced this pull request Mar 11, 2017

Ariel Ben-Yehuda
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
6029d38

arielb1 pushed a commit to arielb1/rust that referenced this pull request Mar 11, 2017

Ariel Ben-Yehuda
Rollup merge of rust-lang#40319 - eddyb:it's-"unsize"-not-"unsound", … 
…r=nikomatsakis

Disallow subtyping between T and U in T: Unsize<U>.

Because `&mut T` can be coerced to `&mut U`, `T` and `U` must be unified invariantly. Fixes rust-lang#40288.
E.g. coercing `&mut [&'a X; N]` to `&mut [&'b X]` must require `'a` be equal to `'b`, otherwise you can convert between `&'a X` and `&'b X` (in either direction), potentially unsoundly lengthening lifetimes.

Subtyping here was introduced with `Unsize` in rust-lang#24619 (landed in 1.1, original PR is rust-lang#23785).
c886815
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.