Skip to content
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.

Sign up for GitHub

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

Jump to bottom

Add Default to std::alloc::System #59451

Merged
merged 1 commit into from
Mar 28, 2019
Merged

Add Default to std::alloc::System #59451

merged 1 commit into from
Mar 28, 2019

Conversation

TimDiekmann
Copy link
Member

@TimDiekmann TimDiekmann commented Mar 26, 2019 •
edited
Loading

System is a unit struct, thus, it can be constructed without any additional information. Therefore Default is a noop. However, in generic code, a T: Default may happen as in

#[derive(Default)]
struct Foo<A> {
    allocator: A
}

Does this need a feature gate?
Should I also add PartialEq/Eq/PartialOrd/Ord/Hash?

@rust-highfive
Copy link
Collaborator

r? @rkruppe

(rust_highfive has picked a reviewer for you, use r? to override)

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Mar 26, 2019
@Centril Centril added the relnotes Marks issues that should be documented in the release notes of the next release. label Mar 27, 2019
@Centril Centril added this to the 1.35 milestone Mar 27, 2019
@Centril Centril added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. needs-fcp This change is insta-stable, so needs a completed FCP to proceed. labels Mar 27, 2019
@Centril
Copy link
Contributor

Centril commented Mar 27, 2019

Randomly reassigning to T-libs member, r? @sfackler

@sfackler
Copy link
Member

Trait impls are automatically stable, so no need for a feature gate here.

Let's not add Hash/Eq/etc yet - they're a bit silly since this type's a unit struct after all.

@bors r+ rollup

@bors
Copy link
Contributor

bors commented Mar 27, 2019

📌 Commit 8733b2a has been approved by sfackler

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 27, 2019
@Centril Centril removed the needs-fcp This change is insta-stable, so needs a completed FCP to proceed. label Mar 27, 2019
@TimDiekmann
Copy link
Member Author

TimDiekmann commented Mar 27, 2019 •
edited
Loading

Let's not add Hash/Eq/etc yet - they're a bit silly since this type's a unit struct after all.

I think this was the exact reason, why Default wasn't implemented. IMO a trait should be implemented regardless of its structure as generic code does not care if it's a unit struct or not.

Centril added a commit to Centril/rust that referenced this pull request Mar 27, 2019
@Centril
Rollup merge of rust-lang#59451 - TimDiekmann:patch-1, r=sfackler
2fefc07 
Add `Default` to `std::alloc::System`

`System` is a unit struct, thus, it can be constructed without any additional information. Therefore `Default` is a noop. However, in generic code, a `T: Default` may happen as in

```rust
#[derive(Default)]
struct Foo<A> {
    allocator: A
}
```

Does this need a feature gate?
Should I also add `PartialEq/Eq/PartialOrd/Ord/Hash`?
@Centril Centril mentioned this pull request Mar 27, 2019
Closed
Centril added a commit to Centril/rust that referenced this pull request Mar 27, 2019
@Centril
Rollup merge of rust-lang#59451 - TimDiekmann:patch-1, r=sfackler
a077493 
Add `Default` to `std::alloc::System`

`System` is a unit struct, thus, it can be constructed without any additional information. Therefore `Default` is a noop. However, in generic code, a `T: Default` may happen as in

```rust
#[derive(Default)]
struct Foo<A> {
    allocator: A
}
```

Does this need a feature gate?
Should I also add `PartialEq/Eq/PartialOrd/Ord/Hash`?
@Centril Centril mentioned this pull request Mar 27, 2019
Closed
Centril added a commit to Centril/rust that referenced this pull request Mar 27, 2019
@Centril
Rollup merge of rust-lang#59451 - TimDiekmann:patch-1, r=sfackler
d04b1ec 
Add `Default` to `std::alloc::System`

`System` is a unit struct, thus, it can be constructed without any additional information. Therefore `Default` is a noop. However, in generic code, a `T: Default` may happen as in

```rust
#[derive(Default)]
struct Foo<A> {
    allocator: A
}
```

Does this need a feature gate?
Should I also add `PartialEq/Eq/PartialOrd/Ord/Hash`?
@Centril Centril mentioned this pull request Mar 27, 2019
Closed
cuviper added a commit to cuviper/rust that referenced this pull request Mar 28, 2019
@cuviper
Rollup merge of rust-lang#59451 - TimDiekmann:patch-1, r=sfackler
44c411e 
Add `Default` to `std::alloc::System`

`System` is a unit struct, thus, it can be constructed without any additional information. Therefore `Default` is a noop. However, in generic code, a `T: Default` may happen as in

```rust
#[derive(Default)]
struct Foo<A> {
    allocator: A
}
```

Does this need a feature gate?
Should I also add `PartialEq/Eq/PartialOrd/Ord/Hash`?
@cuviper cuviper mentioned this pull request Mar 28, 2019
Merged
bors added a commit that referenced this pull request Mar 28, 2019
@bors
Auto merge of #59471 - cuviper:rollup, r=cuviper
d20e000 
Rollup of 18 pull requests

Successful merges:

 - #57293 (Make some lints incremental)
 - #57565 (syntax: Remove warning for unnecessary path disambiguators)
 - #58253 (librustc_driver => 2018)
 - #58837 (librustc_interface => 2018)
 - #59268 (Add suggestion to use `&*var` when `&str: From<String>` is expected)
 - #59283 (Make ASCII case conversions more than 4× faster)
 - #59284 (adjust MaybeUninit API to discussions)
 - #59372 (add rustfix-able suggestions to trim_{left,right} deprecations)
 - #59390 (Make `ptr::eq` documentation mention fat-pointer behavior)
 - #59393 (Refactor tuple comparison tests)
 - #59420 ([CI] record docker image info for reuse)
 - #59421 (Reject integer suffix when tuple indexing)
 - #59430 (Renames `EvalContext` to `InterpretCx`)
 - #59439 (Generalize diagnostic for `x = y` where `bool` is the expected type)
 - #59449 (fix: Make incremental artifact deletion more robust)
 - #59451 (Add `Default` to `std::alloc::System`)
 - #59459 (Add some tests)
 - #59460 (Include id in Thread's Debug implementation)

Failed merges:

r? @ghost
@bors bors merged commit 8733b2a into rust-lang:master Mar 28, 2019
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request May 31, 2019
@jperkin
rust: Update to 1.35.0.
6e0b39c 
Version 1.35.0 (2019-05-23)
==========================

Language
--------
- [`FnOnce`, `FnMut`, and the `Fn` traits are now implemented for `Box<FnOnce>`,
  `Box<FnMut>`, and `Box<Fn>` respectively.][59500]
- [You can now coerce closures into unsafe function pointers.][59580] e.g.
  ```rust
  unsafe fn call_unsafe(func: unsafe fn()) {
      func()
  }

  pub fn main() {
      unsafe { call_unsafe(|| {}); }
  }
  ```


Compiler
--------
- [Added the `armv6-unknown-freebsd-gnueabihf` and
  `armv7-unknown-freebsd-gnueabihf` targets.][58080]
- [Added the `wasm32-unknown-wasi` target.][59464]


Libraries
---------
- [`Thread` will now show its ID in `Debug` output.][59460]
- [`StdinLock`, `StdoutLock`, and `StderrLock` now implement `AsRawFd`.][59512]
- [`alloc::System` now implements `Default`.][59451]
- [Expanded `Debug` output (`{:#?}`) for structs now has a trailing comma on the
  last field.][59076]
- [`char::{ToLowercase, ToUppercase}` now
  implement `ExactSizeIterator`.][58778]
- [All `NonZero` numeric types now implement `FromStr`.][58717]
- [Removed the `Read` trait bounds
  on the `BufReader::{get_ref, get_mut, into_inner}` methods.][58423]
- [You can now call the `dbg!` macro without any parameters to print the file
  and line where it is called.][57847]
- [In place ASCII case conversions are now up to 4× faster.][59283]
  e.g. `str::make_ascii_lowercase`
- [`hash_map::{OccupiedEntry, VacantEntry}` now implement `Sync`
  and `Send`.][58369]

Stabilized APIs
---------------
- [`f32::copysign`]
- [`f64::copysign`]
- [`RefCell::replace_with`]
- [`RefCell::map_split`]
- [`ptr::hash`]
- [`Range::contains`]
- [`RangeFrom::contains`]
- [`RangeTo::contains`]
- [`RangeInclusive::contains`]
- [`RangeToInclusive::contains`]
- [`Option::copied`]

Cargo
-----
- [You can now set `cargo:rustc-cdylib-link-arg` at build time to pass custom
  linker arguments when building a `cdylib`.][cargo/6298] Its usage is highly
  platform specific.

Misc
----
- [The Rust toolchain is now available natively for musl based distros.][58575]

[59460]: rust-lang/rust#59460
[59464]: rust-lang/rust#59464
[59500]: rust-lang/rust#59500
[59512]: rust-lang/rust#59512
[59580]: rust-lang/rust#59580
[59283]: rust-lang/rust#59283
[59451]: rust-lang/rust#59451
[59076]: rust-lang/rust#59076
[58778]: rust-lang/rust#58778
[58717]: rust-lang/rust#58717
[58369]: rust-lang/rust#58369
[58423]: rust-lang/rust#58423
[58080]: rust-lang/rust#58080
[57847]: rust-lang/rust#57847
[58575]: rust-lang/rust#58575
[cargo/6298]: rust-lang/cargo#6298
[`f32::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f32.html#method.copysign
[`f64::copysign`]: https://doc.rust-lang.org/stable/std/primitive.f64.html#method.copysign
[`RefCell::replace_with`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.replace_with
[`RefCell::map_split`]: https://doc.rust-lang.org/stable/std/cell/struct.RefCell.html#method.map_split
[`ptr::hash`]: https://doc.rust-lang.org/stable/std/ptr/fn.hash.html
[`Range::contains`]: https://doc.rust-lang.org/std/ops/struct.Range.html#method.contains
[`RangeFrom::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeFrom.html#method.contains
[`RangeTo::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeTo.html#method.contains
[`RangeInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.contains
[`RangeToInclusive::contains`]: https://doc.rust-lang.org/std/ops/struct.RangeToInclusive.html#method.contains
[`Option::copied`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.copied
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees

@sfackler sfackler

Labels
relnotes Marks issues that should be documented in the release notes of the next release. S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
1.35
Development

Successfully merging this pull request may close these issues.
6 participants
@TimDiekmann @rust-highfive @Centril @sfackler @bors @hanna-kruppe